3.0 rough idle
10-01-2004, 10:42 AM
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3.0 rough idle
hey all,
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
10-01-2004, 10:52 AM
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I'm having the same issues with my 3.0. I plan on changing the plugs and all the fluids this weekend. I'll also be checking air flow and what not. If any of what I do this weekend helps I'll let you know.
10-01-2004, 10:58 AM
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Originally Posted by jay-q
hey all,
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
10-01-2004, 11:09 AM
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I've had the same problem with my 1995 3.0 engine for a couple of years. It started as a very slight problem and gradually got worse. I've changed plugs, wires, cap, rotor, fuel filter, cleaned the throttle body and a whole host of other junk with no help. I took it to a couple of places and all of them said it was fine. Finally one dealer said the injectors were leaking and causing the problem. I changed the injectors myself and guess what.... it didn't fix the problem! Wasn't too happy about that.
It's not using oil or water and for the life of me I can't find the problem. I especially notice it during the warming up phase or slow speed driving at constant speed (like in freeway traffic). If the engine is cold I don't feel it. I notice the miss mainly in the 2500 RPM range as a miss and surge. I finally decided that since it was still running fine for the most part and getting good gas mileage and not using any oil and water that I'd just have to live with it.
Sorry this isn't much help other than to tell you what didn't work for me.
It's not using oil or water and for the life of me I can't find the problem. I especially notice it during the warming up phase or slow speed driving at constant speed (like in freeway traffic). If the engine is cold I don't feel it. I notice the miss mainly in the 2500 RPM range as a miss and surge. I finally decided that since it was still running fine for the most part and getting good gas mileage and not using any oil and water that I'd just have to live with it.
Sorry this isn't much help other than to tell you what didn't work for me.
Last edited by Steveh29; 10-01-2004 at 11:11 AM.
10-01-2004, 11:27 AM
#5
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Originally Posted by jay-q
hey all,
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
im having trouble diagnosing my rough idle problem. it is ever so slight. the engine will idle erratic (tach needle bobbs up and down slightly). also engine will stumble some during initial acceleration. i am noticing during slow acceleration, but it may be prevalent during hard acceleration.
another thing, when the car is warm, the car will idle fine for the most part but will also have a sort of misfire,if you will, every 10-15 seconds or so. the car runs fine otherwise.
i'm fairly sure, that the problem developed after the dealer performed a tune up on it. which was a month ago. it ran excellent before then. i brought it back to them and tried to explain the problem, they had 2 mechanics look at it and told me that is the normal idle for this engine with 133K miles.
im in the carmel valley part of san diego, wondering if there are any 3.0 experts on this board around my area willing to listen to my engine, so that i know im not imagining it. i guess i just want a confirmation that there is an idle problem, before i pursue trying to service it.
or if there are any suggestions you think i should do. the dealer changed the plugs. i'm almost up to changing them again, just to eliminate it as a suspect.
i think it may be the tps but, i read the write-up on it and don't think i am good enough to mess with it. im afraid i might make it worse.
anyhow, thanks in advance for any help
JQ
Since all of this started after the tune-up it leads me to believe that the mechanics screwed something up at the "stealership". An incorrect gapped plugs will give you a miss like you explained, the correct gap is .031.
Also, check to make sure that you have no loose plug wires, nor vac lines and that your air intake is tightened correctly. I'd also re-spec your TPS, it's easy as pie, all you need is a multi-meter, you can get one from Wal-Mart for under $20!
p.s. That's not a normal idle even if it has 133,000 on it, they're full of sh**! Mine had over 277,000 on it before I rebuilt it and it idled great!
Good Luck!
10-01-2004, 11:50 AM
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wow.... fast replies.... thanks.....
forgot to mention,
i first made sure the wires were on good and tight and in the right order, they were.... also, i replaced the cap and rotor, and it didn't make a difference. i've even added chevron fuel cleaner to a couple of fill ups, with no difference noted... and i checked out the throttle body.... it was cleaned out by the dealer...
in regards to the idle set screw, i increased it last saturday and noticed that the engine still behaved the same only at higher revs, so i returned it the original setting.
please keep the suggestions coming. nunsa, i will check the gapping on the spark plugs sometime this weekend... i do have a fluke multimeter and the feeler guages but i still have reservation doing the tps. are there mechanics or service shops that would perform this for me?
forgot to mention,
i first made sure the wires were on good and tight and in the right order, they were.... also, i replaced the cap and rotor, and it didn't make a difference. i've even added chevron fuel cleaner to a couple of fill ups, with no difference noted... and i checked out the throttle body.... it was cleaned out by the dealer...
in regards to the idle set screw, i increased it last saturday and noticed that the engine still behaved the same only at higher revs, so i returned it the original setting.
please keep the suggestions coming. nunsa, i will check the gapping on the spark plugs sometime this weekend... i do have a fluke multimeter and the feeler guages but i still have reservation doing the tps. are there mechanics or service shops that would perform this for me?
Last edited by jay-q; 10-01-2004 at 11:55 AM.
10-01-2004, 06:40 PM
#7
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Originally Posted by jay-q
wow.... fast replies.... thanks.....
forgot to mention,
i first made sure the wires were on good and tight and in the right order, they were.... also, i replaced the cap and rotor, and it didn't make a difference. i've even added chevron fuel cleaner to a couple of fill ups, with no difference noted... and i checked out the throttle body.... it was cleaned out by the dealer...
in regards to the idle set screw, i increased it last saturday and noticed that the engine still behaved the same only at higher revs, so i returned it the original setting.
please keep the suggestions coming. nunsa, i will check the gapping on the spark plugs sometime this weekend... i do have a fluke multimeter and the feeler guages but i still have reservation doing the tps. are there mechanics or service shops that would perform this for me?
forgot to mention,
i first made sure the wires were on good and tight and in the right order, they were.... also, i replaced the cap and rotor, and it didn't make a difference. i've even added chevron fuel cleaner to a couple of fill ups, with no difference noted... and i checked out the throttle body.... it was cleaned out by the dealer...
in regards to the idle set screw, i increased it last saturday and noticed that the engine still behaved the same only at higher revs, so i returned it the original setting.
please keep the suggestions coming. nunsa, i will check the gapping on the spark plugs sometime this weekend... i do have a fluke multimeter and the feeler guages but i still have reservation doing the tps. are there mechanics or service shops that would perform this for me?
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
Anyone can perform this, but they're going to charge you at least $25 or more! You have the tools so do it yourself! If you are unsure, just scribe a mark on the tps so you are sure to put it back in it's position in case you make a mistake! 10-4?
Good Luck!
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10-18-2004, 10:24 AM
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tps adjustment
ok...
over the weekend, i replaced the sparkplugs.... i did notice that the plugs on the 1 and 2 cylinder were less than .031 gapped...
the engine now runs a little better, but i still notice the "miss" once in a while....
i tried adjusting the tps to see if i could get any further improvement.... i used the tps webpage as a guide.... i did not take the throttle body off the engine... basically.... i was not able to get the ohm readings it lists.... and it is a pita to get the meter clips to stay on....
i gave up and just installed it on to as close to where it was as i could remember.... (i replaced the screws with allen head screws as suggested)
started up the car and it seems like its the same.... hopefully i didn't misadjust it....
anyhow.... with that said.... it does idle a bit better, albeit not as smooth as i remember it used to idle....
thanks for everyones help on this
JQ
over the weekend, i replaced the sparkplugs.... i did notice that the plugs on the 1 and 2 cylinder were less than .031 gapped...
the engine now runs a little better, but i still notice the "miss" once in a while....
i tried adjusting the tps to see if i could get any further improvement.... i used the tps webpage as a guide.... i did not take the throttle body off the engine... basically.... i was not able to get the ohm readings it lists.... and it is a pita to get the meter clips to stay on....
i gave up and just installed it on to as close to where it was as i could remember.... (i replaced the screws with allen head screws as suggested)
started up the car and it seems like its the same.... hopefully i didn't misadjust it....
anyhow.... with that said.... it does idle a bit better, albeit not as smooth as i remember it used to idle....
thanks for everyones help on this
JQ
10-19-2004, 01:23 PM
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I just found the root cause of my rough idle. It was two things.
1. The coolant line that goes through the throttle body was plugged tight. No coolant was going through at all. I happened to have an extra throttle body that is good and switched it out and prest problem gone.
2. The IAC valve that is on the side of the throttle body was full of oil that I can only guess got there cause of a plugged or semi plugged PCV valve. The plugged PCV valve causes oil to be sent back throught the intake and can clog stuff up. The gasket also had a rip in it and i think it acts as a membrane of sorts.
My solution for replacing the pcv valve easily was to drill one out and put it in the stock location the put another in-line out from underneath the intake plenum.
Just my two cents. Hope it helps
1. The coolant line that goes through the throttle body was plugged tight. No coolant was going through at all. I happened to have an extra throttle body that is good and switched it out and prest problem gone.
2. The IAC valve that is on the side of the throttle body was full of oil that I can only guess got there cause of a plugged or semi plugged PCV valve. The plugged PCV valve causes oil to be sent back throught the intake and can clog stuff up. The gasket also had a rip in it and i think it acts as a membrane of sorts.
My solution for replacing the pcv valve easily was to drill one out and put it in the stock location the put another in-line out from underneath the intake plenum.
Just my two cents. Hope it helps
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