95Bird

Well i have a 96 TA that im doing for fun. My problem is it has developed a bad miss/rich problem. Its the left bank. When the car is cold on a fresh start both 02s show in the high 480s. As they heat up my right bank goes up as it should but the left 02 drops until it settles in the high 100s to low 200s. I've tried everything. Swapped o2s, put in spare O2s in left side. Swapped the extenstions from left to right side, Pulled the injectors and preassured up and didn't see any leaks. I'm really at a loss. Put new wires on, changed plugs, and even threw on a spair opti i had laying around. I even went as far as converting the car from obdII to obdI with a computer i had sitting around from my 95. Im out of ideas. Can anyone lead me in any direction. I know its a false lean condition as the unburnt fuel is causing it. It gets to where the car is missing its running so bad/dumping fuel and it burns your eyes if you stand behind it. Fuel trims are good on the right bank at 128 but on the left bank its shoots to the 140s/150s once it goes into closed loop. Someone has to be able to point me in a direction i haven't thought of

Ricardo

Could it be a bad injector on the left bank? One cyl w/o fuel would make the O2 sensor read lean and the fuel trims would climb up on that bank to compensate. If you have not tried this you can switch the injectors from one side to the other. The exhaust would also be cold on a non firing cyl.
Just a thought.

cthomson21

I have had some of the same problems before. I would agree with ^ as this is a possibility. Another thing to check would be the exhaust manifold/header gasket between the manifold and head. If its blown I believe you will get faulty readings. I would pull the plugs and see which ones if any are gas fouled. If all of them are this is probably where I would start. If only one or two check the injectors like ricardo said. When I bought my car the plug wires were crossed and it caused all sorts of problems, so check stuff like that too since you said you had changed all of that, although not sure how this affects the o2 reading. Also, I haven't been working on these cars long so take what I say with a grain of salt. This is just what has happened with my car in the past. Hope I helped and good luck.