Running "lean", hot, and missing...Last Try

SCollord90

Registered User
Well, I've been chasing this problem for a couple weeks now and about to break down and go to a dealership to just let them diagnose it so I can fix it. Here are the symptoms:

1) The car has been running up as far as the middle of the temp gauge and is normally only in the first quarter.

2) My standing idle in "drive" is at about 11-12 (keep in mind I'm high elevation)

3)Once my engine warms up it starts missing, dipping down when I slow down, and stuttering while I stay stopped. I can feel the car miss and then catch up as I'm driving with it getting worse as I drive longer.

4) I keep getting codes saying both sides are lean and a scanner tool (which for some reason couldn't get specifics on anything) verified this. HOWEVER, the O2 sensors look rich when I pull them.

5) So far one time while on the interstate the rpm's started bucking up and down and eventually resetting to normal after stopping and a short wait.

6) I'm not sure if this is related but I've heard backfires in my exhuast while I coast. The weird thing is my vacuum can get up to 19 when I'm coasting which is high for here.

Now I've checked the plugs, wires, BAP, replaced the Cam sensor, replaced a O2 sensor that melted to my header, my coolant doesn't look milky. I have been looking at lots of searches and nothign seems to explain this.

Raptor had suggested that my current problem could be caused by a broken damper. If it is truly broken would I be able to see if I removed the plastic "sheilds"?
 
I should also mention that I have a 93 style MAF with those electronics on my 90. If I'm not mistaken I need the 90 electronics in the 93 unit. That could explain the lean or rich condition but I've had it in for months without any problems.
 
things to check for as far as your balancer. first, verify that the middle bolt is still there. then, with the engine running, check the crank pulley for excessive wobble. also if the upshift light stays on while cranking, it could be bad. and lastly, if you can rotate the outer ring of the balancer on the inside of it, its definitely bad. i dont know if you have to take the plastic cover off to do this though. theres a rubber piece that separates the outside from the inside that dry rots and causes it to fail. as far as other reasons why your car is doing this, its going to take someone a bit more experienced than i am. good luck man.
 
DIS module?, cam sensor? Try changing the heat sink compound under the DIS module. Is your tach acting up when it stutters?
 
sounds like the samething I have had happening for the last little bit. the only thing is the codes I get are 41 and 91 O2'S out of range.
 
Could be a loose ground wire

On the back of the driver's side head (where the fuel rail bracket mounts) there is a wire. This wire is the ground for the O2 sensors. Check that ground.

Also, do you have any header leaks at the head (prior to the O2 sensors)?
This would cause a lean condition too.

Good luck
 
well...

Ok let here it goes:

3TBird- I will check the ground but I don't think that is the problem. Either way its worth a check.

Jason Wild- Those are the same exact codes that I keep getting.

Specops_sc- My middle bolt is still there but I think I saw that my crank pulley did have some wobble to it. As for the upshift light I don't think mine is coming on but the previous owner installed white face gauges that eliminate the little arrow and replace it with a block. When I crank it the light on the right (I think the "check gauge") light is on. I guess its time to check the balancer either way.

I'll keep you posted if anything new develops.
 
I have looked at that ground on the rear of the head befor and it had been broken but since I have fixed it two times. I think it might be the DIS I might just need to change it and give it a try.
 
Well unless things change it seems that I got some reallllllllllllllllllll ****** gas from silver city. just in case anybody is searching and has the same problem. I just added some HEET (or HEAT) whichever. Seem to be gone.
 
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