hub_01_69

Could anyone help me out with this? The truck runs great driving down the road but when I come up to a stop light the idle drops dramatically to 500-200 rpm. Even if I bump it into neutral it only goes up to 500-600 rpm. The engine has approx 33,000 miles, has new air filter, i've cleaned the throttle body, intake manifold, had the injectors rebuilt by cruznperformance, new fuel filter, coolant is topped off, new dist cap, rotary button, wires, plugs (I tried these after searching on here) and still has rough idle. I checked on 4crawler's "cheap tricks" sight last night and checked the codes using a paper clip this mornin in the parking lot a work and it gave me a code 4 http://www.4crawler.com/4x4/CheapTri...osticcodes.gif
It says the water temp sensor. Could this be causing the aweful idle problem? How do I clear the codes on a OBDI system? Sorry for the long post. Thanks for any help

Buck01

you can disconnect the battery to clear the code.

if the truck does not reach normal temp then it could be running with the cold start injector. This would make it run rich and tend to make it stumble like a carb vehicle with the choke stuck.

check coolant level and check temp sensor.

just my thoughts on this issue.. good luck.

hub_01_69

Thanks Buck. The coolant level is fine and the temp gauge reads normal operating temp but if the sensor is messed up then it could be signaling the ecu that it hasn't reached operating temp and could be running with the cold start injector correct?

hub_01_69

I have replaced the water temp sensor and it's not showing any codes anymore but i'm still having a problem with my idle. I forgot to mention but it idles fine while cold it's just when it starts warming up is when it starts having a problem. Could it be the O2 sensor? Running fine while cold and in open loop but then has trouble when it goes to closed loop? Anyone have any ideas?

MMA_Alex

im currently dealing with a rough warm idle issue too. I thought the dash coolant temp guage, and the ecu temp reading came off different sensors. I seem to remember reading that somewhere, but maybe someone can confirm?

trythis

I will sugest egr system. It is connected to teh temp sensor, at least the egr system has one, but if yours is new, that would be a surprise to find it gunkeed up that fast

hub_01_69

MMA_Alex, you're right. The temp gauge gets it's signal from the temp sending unit which is located on the pass side of the engine block and the ecu gets it's signal from the temp sensor which is located on the front of the engine block (22re). I've got an 02 sensor on the way. Whether or not it's the problem, it probably wont hurt anything to be replaced anyways since it's 15 years old. It's very possible that it could be this bad boy right here: http://www.partsamerica.com/ProductD...pe=757&ptset=A

toyotaoffroad91

so did you fix your problem yet

hub_01_69

nope still haven't completely solved the problem...I replaced the o2 sensor today but it still doesn't idle like it should...especially when in gear.

lVlr_87

I have the same issue, runs fine until it warms up. Funny I am working on it today. I thought it was my EGR valve because when I plugged the vaccum line going into the top of the egr it made run a little better. I bought a new EGR valve and O2 censor and it is still running rough. Even under load it misses and skips and idles real low and dies. All of this started last year when I accidentally dunked it and killed the engine. My engine is a new Jasper remanufactured engine with about 15,000 miles on it. I need help- I am frustrated.

Toyopnoy

I have an idle issue as well and is somewhat similar to what everyone is saying. I believe the rough idle at initial start up has to do with the cold start injector sensor going bad. But my problem just happened recently. I changed the oil and plugs and did a seafoam treatment prior. I put the denso regular plugs and gapped them to I believe .035. When I am at a stoplight the idle sometimes stumbles. Other than that they truck runs great no problem under power just on idle sitting at the stoplight. Any ideas?

curly_c

samething here. when warm its low and choppy. i cleaned the TB twice. the day that i clean it it runs like a champ. then it goes back to doing it. i have no idea what the problem is

rdharper

One common cause for this is the TPS (throttle position sensor) not adjusted correctly. The sensor has a bit of a knife edge adjustment. If the sensor tells the ECU your throttle is not at the idle position, then the ECU will do its damnedest to lower the rpm. 500rpm seems to be the point where the ECU stops trying to lower idle any further.

Note the TPS report to the ECU is like a switch in the sense that you are either at idle, or not. Search on <idle adjust> will bring up lots of info.

MMA_Alex

like i said ive been dealing with the same issue. i cleaned the maf with no luck. tonight i tried the idle adjust screw. I played around with it a little and now it seems to idle smoothly, however i dont have a tach to check the rpm.

lVlr_87

So far I have replaced O2 sensor, EGR valve, Throttle Position Sensor, and MAF sensor with no luck. I am tired of guessing and spending $$$. I am going to try to take back most of the parts I bought and it is going to the dealer in the morning. I will let you guys know what they say. I hate to take it there, but I have to drive this thing from WA to AL and then up to MO in less than 2 weeks so I just have to get it fixed. They said it would cost me $45 to $180 to diagnose it so it is almost worth it to me.

curly_c

so the strangness continues. just now on my way home from work my idle dropped down to 200!! and when i would accelurate my RPMs would shoot up. i would have to shift about 5-7 mph earlier than i would normally. and my engine was really really quiet. i DIDNT loose any power or pep though. and when it was idling that low it still was smooth as silk. if i didnt have a tach i wouldnt know it was that low. then after about 2 mins it stopped. went back to normal. it was very odd.

TNRabbit

I would definately check the TPS and also for those of you who didn't state anything in this post about doing so, adjust your idle air control screw!

Toyopnoy

Wish I had a tach so I knew what the RPMs are at instead of doing it by ear haha...

hub_01_69

After a couple of days driving with the new o2 sensor it idles smooth again. It's only about 6 or 700 rpm in gear but it's no longer shaking and such. Is that the normal rpm for an auto while in gear and idling?

rdharper

Should be 800rpm. If all else remains well, I wouldn't worry about it. My earlier advice on the TPS was based on experience with my V6. I have a 22re as well, but haven't had the TPS problem on it, although I suspect they work identically. If the TPS doesn't show an idle position to the ECU, it will lower the rpm to 500 and stop there, if nothing else is wrong. It is an adjust problem that seems to be common, as the adjustment is knife edge. Also, the dashpot or throttle linkage can give a slight resistance whereby the throttle doesn't return fully. Enough for now, if you have no other problems, as I said, I'd leave it, or maybe try to adjust up the rpm's slightly.