alowell

Just an update guys. Switched the coils and a 1 & 4 misfire still popped up in the codes after I pulled the fuse and cleared the codes. Therefore, I ruled it back to the one event and the one thing all the codes might have been linked to, the MAF sensor. I picked one up from the dealer and popped it in. No more check engine light and the engine is running much smoother. I'll have to track my MPG this week and make sure that is up to snuff again too. Greased all the connections too, I will be doing that from now on. Might change the plugs next week for tune up anyway, I think I set the gap incorrectly on them last time and that can't be heling anything. Thanks for all the help, you guys

alowell

OK, so here is the deal now. Put in new MAF sensor and a new ignition coil (1 and 4) and changed the plugs again. Still a rough idle and decreased MPG!!!!!!! Any ideas? Thought everything was fine, but apparently not, it ran well for about a day and then back to the usual.

eddieleephd

Ok what plugs did you install??? Have you tried to clean the o2 sensors?? Did you Di-electric all connections and have you ran seafoam through the tank?
Plugs are important which type you use will help or hurt this is big. o2 sensor may be an issue what it reads is important mostly the front one. and if your injectors have an issue this could cause the issue hence seafoam.
When does it run roughest? engine load Hot Cold duration of run time???
Does it run rougher at start or after warm up? Can you check the pressure on the fuel rail?

alowell

NGK platinums. Haven't cleaned the O2 sensors yet. Used di-electric per your suggestion on all connections. I ran seafoam into the intake to clean the throttle body in front of the butterfly valve and also ran it in the oil prior to changing. Should I run it in the tank now? IT runs the roughest first thing in the morning on a cold start and gets a little better once at temp, but still rough. I'd have to get a gauge to read the fuel pressure and not sure if the 98 taco has the reading valve on it, I'd have to check.

eddieleephd

No reading valve you have to use a banjo fitting. Yes you should run the foam through the tank. and I am just making sure that these platnums are dual ground. And make sure to reset the ecm by disconnecting the battery for 15-20 minutes so it has to relearn fuel curves and maf readings.

alowell

These are the plugs:
http://www.ngksparkplugs.com/product...310&country=US

I'll try running seafoam through and then disconnecting the battery again. This is the right stuff, right?

http://www.seafoamsales.com/motor-treatment/index.html

Thanks Eddie

eddieleephd

Yes that is the stuff. Is the plug that you installed the same as the pic? single ground??
I ask because it is eminent that you use a dual ground plug such as in the following two links.

http://www.sparkplugs.com/more_info....72596&pid=2708

http://www.sparkplugs.com/more_info....72596&pid=9642

or I run an NGK BKUR7-et this is a two step cooler plug that is more recommended for super charged trucks

if you installed a single ground I suggest you install a dual ground plug and see what happens.
If you decide to use the BKUR7-ET I will tell you it will idle a little rough at 750rpm idle because it is a 2 step cooler plug.

the platnum plug you want is BKR5EKPB-11 by NGK
found
http://www.ngksparkplugs.com/part_fi...uv/results.asp

after looking at the g-power on the previously posted web page I believe you need to go with the laser platinum.

alowell

You think it would make that big of a difference? I would think that brand new plugs would act the same no matter if they were single or dual ground. I'll have to try that out. Have you personally noticed differences from the brand new single ground vs. the dual ground? Woudl this also account for the decrease in about 4 MPG?

eddieleephd

Yes actually I have especially with the small tip on the electrode and single ground. mine worked fine for about 1000mi then crap. I started using the recommended plugs and nothing bad since. so try the better dual ground plugs and see what happens. E3 are no good for our trucks either if you want platnum plugs use NGK BKR5EKPB-11. like I said the ones I use are BKUR7-ET they have a copper electrode and I have only found them at advance but they are recommended more for forced air intake.

http://shop.advanceautoparts.com/web...S_542768499___

advanced carries the Denso below are cheaper than NGK above is the NGK link

http://shop.advanceautoparts.com/web...S_891105941___

master tech1

eddieleephd U may be rite abt O2s but on most cars itll be a O2 problem when the car runs like as soon as it heats up not when cold. but the O2 is a simple check, but if it was my truck i wouldnt clean them i would replace, they r cheap on most cars

Just to clarify the misfire occuried after the worked u did? im confused by ur first comment at the start it sounds like the problem has been going on for awhile, then at the end u say it started when u did the work so which is it?

And Why havnt U cheaked the plugs like they told u earlier? What plugs came out origanally?

Um and u shouldn't have to set the gap on ngk platnium plugs? at all. IF when u pull the plug out of the box and ther is a little cover the threads, electrod, and ground then do not set gap.

if the problem has been going on for awhile then i would check compression in all cylinders (wet and dry compression test)

if not then check pulse width,

by the way i have a 2000 2.7l and it runs fine with ngk single ground, so i need u to ansewer ALL of my questions

alowell

I did the work and then the problem started. I was just replacing starter contacts and doing maintenance on the truck (plugs, MAF, starter contacts). I decided to replace the fuel filter while I had the starter out too. After all of the work, my MPG decreased and rough idle. IS it possible messing with the fuel filter caused something? That was about 6 weeks ago and I have been trying to figure it out since.

I have checked the plugs and replaced them twice, NGK platinum came out and new NGK platinums went in.

Double checked the gap on the NGK and made sure it was right, I think .032. There wasn't much adjusting.

The engine is definitely firing rough and there is considerable vibration. Is cleaning the injectors a do-it-yourself job or not? BTW, I seafoamed the tank, crankcase, and intake last night. I heard that might help as well to clean the injectors and such.

eddieleephd

How long has it been since you put new wires on? The reason that I ask is that they can be fragile pulling them off can damage them then the vibration of the engine will do the rest.
I still am leaning towards plugs I have a '99 it is a 6 cyl but never had any luck with single ground plugs. and if you look at the pics you can see that the spark on the dual ground plugs happens closer to the fuel and the single ground is farther away.

alowell

Yeah, I was thinking the wires might be it too. It has been about 3 years since I put in new wires.

alowell

You think it has anything to do with the fuel filter I installed 6 weeks ago. It seems like this is the only thing I haven't explored as a cause.

alowell

I guess I woudl have to check the resistance through the wires, right? Any idea what the resistance is supposed to be?

eddieleephd

I would say to go get the plugs and wires replace the plugs first, then the wires if it does not clear up. But do it one at a time either way you do it, wires first, then plugs. This way you will know what the issue is. The reason that I keep pushing plugs is the single ground and the intensity of the spark of our trucks. Tech1 says that his runs fine with single ground but his is a 2000 and I am not sure what they changed and like he said in another post that different people have different experiences. I have never had good luck with single ground plugs in my truck.

http://www.ncttora.com/fsm/2000/Repa...20Pump/ovi.pdf

here are the fuel pump specs for testing I really do not think that the filter is the issue because it runs. What type of filter did you install? Usually if it is the filter it will stall at high rpm due to lack of fuel at the rail.

I would point you to cam and crank sensors if you did not get this problem after the work performed and that just is unlikely, possible but highly unlikely.

Did you ever reset the ECM? disconnect battery for 15min or over night? I really hope that you figure this out soon because I know how it feels especially when nobody responds with some kinda input.

Have you recently changed any thing else? Any thing at all???

alowell

Do you guys think that a cracked header or leaky exhaust before the cat converter woudl cause a rough idle and decreased MPG? I noticed the truck is sounding like a go-cart and think I can see a crack in the header.

eddieleephd

Yes That would these trucks require a good amount of back pressure. Would probably have suggested that if it wasn't for the work performed.

master tech1

ehaust leak overtime will burn up ur exhaust valves, how long has it been leaking it takes a long time. plus 4 cylinders need back pressure

im confused i thought u changed ur wires, i guess i just assumed that, first check and make sure u didnt break off metal contact on the wires, just look inside the boot, next when u attach ur wires to the plugs make sure u hear or feel a good solid click thats very important. as far as the ohms across the wires just compare them between the others, but they may all be jacked up, so just get some wires, if u dont need them now u will later. Also if the contacts is still in the wires and u dont hear or feel that good solid click and ur to cheap to get new ones then bend the contacts tighter with a needle nose too make better fit, and use dielectric (that last one was a shout out to u eddieleephd

the double ground thing is a possiblty yes but it ran fine before with the single ground, bc u said that u put the same plugs u pulled out origanlly

injector cleaning there is couple ways to do it, but in my opinion there is only one way that really works, but before u do that check pulse width!, injector cleaning (the right way) without pulling the injectors- first u need to get the 3M injector clean bottle then u gotta buy toyota fuel line adaptor that connects to inlet fuel line at the rail, then disable fuel pump cause u gonna have a open line, then start engine and the truck runs off the bottle until it runs out, this somtimes fouls plugs though, sounds expensive dont it. at my old shop we use to charge $189.99 but it works

i dont think u need to clean injectors. Yet maybe ill think that later after u check everything else but unlikely

alowell

Alright fellas, here's the latest. I took off the heat shield and discovered a cracked header and Thermosteel'd it, because I don't have $400 for a new exhaust header. It seemed to do a good job. I also replaced the wire set. Still runs rough in idle, but I'll have to wait and see how the MPG looks (I just did the repair yesterday). I am not sure how long the cracked header has been there...months...years..weeks? Not sure. At least my truck doesn't sound like a go-kart anymore..that's one positive. IF it doesn't change anything, I'm thinking it could be the exhaust valves. Though I don't have a check engine light anymore, but that could change too. I'll keep you updated.