lazlow

Hey ive got a 97 3.4 5 speed in my truck and it decided to give me a problem. A little background first. Bought the truck and it had a horribly high idle, first cleaned the throttle body and iac and replaced tps. Didnt do anything so my friend brought over his smoke machine and we discovered just about every vacuum line leaked. Fixed that and the truck idled perfect and drove good. Drove it about 20 miles to and from school for a week and a half.

Yesterday it had a high idle of about 1100 or 1200 so i checked on my scanner and the tps was reading 91% at that! So put the old one back on and its back to 12ish at "idle". Here is where the problem comes in. Now when it idles down it it starts running super rich and stumbling and just about stalling surging from about 1000 to 200 on the tach and back and forth. stft is reading -20.3 at the time and ltft reads -19ish. Rev it to 1500 and ltft goes to 0 and stft goes to around -2 and fluctuates a bit. o2 sensor is reading 1.245 i believe and stays there. Only code ive gotten it to give was rich condition and it occasionaly gave a late response code from o2 sensor the past week of driving.

Im suspecting o2 sensor either way but would it cause it to run THAT rich? Also cleaned maf which didnt help. Running out of ideas here. MAF wasnt giving any weird signals and everything else seemed fine. Please help lol

lazlow

I had an idea that a bad exhaust leak was part of the problem and i was part way right. After the crossover at the flange the exhaust bolts loosened up and there was a huge gap. I thought that exhaust gasses were leaking out showing the o2 sensor a lean condition and it was overcompensating by richening it too much. Truck sounds better and idle better at first but same symptoms come back.

Now it is giving me a random misfire code, cylinder 2, 4, and 6 misfire codes. No more 0172 code... Any ideas?

sdsurfer

I am no pro by any means but 2 4 6 missfire? that is all on the same side right? might lead to the issue? goodluck! im waiting to see what pros say!

lazlow

the problem seemed to fix itself. I had it in the garage for another day till i got time to move it and when i went to move it the truck was running fine. Exhaust leak must of been the problem but the computer never corrected itself? Oh well picked up a new o2 sensor and will be doing plugs soon. Any other places i should check for regular maintenance or common problems? Ill be doing the timing belt soon to be safe.

And yeah 2 4 6 are the same side which was just confusing the hell out of me...lol oh well drove fine to school..