Misfire and O2 sensor issue
06-10-2004, 03:31 PM
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Misfire and O2 sensor issue Hey all. I posted about this a few weeks ago elsewhere, but the responses dried up. The problem has changed also. Anyways here is the lowdown.
Originally car was misfiring somewhere in the warmup period. Car ran fine for first few mins (from being completely cold). Then would run terrible and misfire for a few mins. I could either ride it out or accelerate heavy to make it "snap" out of it. This lasted until the car warms up fully. Then everything seems ok. If I let the car sit for 10 mins and restart it it acts up again. If I let it sit over night and completely cool. Cycle repeats - runs fine few mins, gets warm, runs crappy, gets hot runs fine. Well my friend put it on his code reader and said my O2 sensors were bad and not giving off any readings. I replaced them and $140 later problem seemed to go away. Well a few days later I noticed it doing it again. Only NOW it only does it when you shut the car off for 10-15 mins and start it again. Runs fine from cold warmup. Also it dosen't last nearly as long - only about 5-10 seconds.
Problem started when I washed under the hood a couple weeks ago and at first I thought it was just something wet. Also I installed my headers about 2 months ago and my EGR, AIR and CATS are all gone. I also discovered I have a broken motor mount, and a slight ticking under the hood which many are saying is an exhaust leak. Any thoughts on this? I read somewhere about bad o2 throwing a code and it having to be programmed out and being in a "safe mode" of operation? I'm about to take it to a professional shop in Flint to look it over. I don't know what else to do! Please help.
Originally car was misfiring somewhere in the warmup period. Car ran fine for first few mins (from being completely cold). Then would run terrible and misfire for a few mins. I could either ride it out or accelerate heavy to make it "snap" out of it. This lasted until the car warms up fully. Then everything seems ok. If I let the car sit for 10 mins and restart it it acts up again. If I let it sit over night and completely cool. Cycle repeats - runs fine few mins, gets warm, runs crappy, gets hot runs fine. Well my friend put it on his code reader and said my O2 sensors were bad and not giving off any readings. I replaced them and $140 later problem seemed to go away. Well a few days later I noticed it doing it again. Only NOW it only does it when you shut the car off for 10-15 mins and start it again. Runs fine from cold warmup. Also it dosen't last nearly as long - only about 5-10 seconds.
Problem started when I washed under the hood a couple weeks ago and at first I thought it was just something wet. Also I installed my headers about 2 months ago and my EGR, AIR and CATS are all gone. I also discovered I have a broken motor mount, and a slight ticking under the hood which many are saying is an exhaust leak. Any thoughts on this? I read somewhere about bad o2 throwing a code and it having to be programmed out and being in a "safe mode" of operation? I'm about to take it to a professional shop in Flint to look it over. I don't know what else to do! Please help.
06-10-2004, 08:31 PM
#2
Do you have LS1 edit or other tuner program? If so, turn the closed loop enable temp to 300 degrees and see if the problem changes at all. If it does change, then it is probably the 02 wiring.