Ok guys I've been searching these forms for hours now, and I can't find and answers. .
So car has been running great for a while now, then outta now where it starts running rough and missing like my wires are arcing. Then it almost dies, the check engine light comes on and it starts running fine. After the car is turned off and I start it back up later it's rough and missing again until the check engine light comes on again. I'm working on getting it scanned but I just haven't had the chance yet, any body got any ideas?

 

Basic info about the car - year, engine, major mods - would be helpful.

Probably a faulty sensor. But why guess... scan will point directly to the problem.

 

Sry thought I had a sig, 97 z28, 160k, cai, lt dual ex, msd 6al, 160 ts, 95 computer swap, tuned by madtuner, new opti, wires and plugs about 5000 miles ago, and icm, iac, o2s.
So I finally got my lab top up and running and did a scan the only code was 64, lean condition bank 2
Bank 1 was reading from 0.2 - 0.9
Bank 2 was reading 0.001 - 0.003
So I'm thinking it's a bad o2 on bank 2
Does that sound right?

 

Could be the sensor, but could also be a wiring problem. Or, the outside of the sensor could be contaminated with something (e.g. - oil) that prevents air from entering the inside of the sensor thimble at the base of the wires.

First inspect for damaged sensor or harness wires, a wire touching the manifold, or something coating the outside of the sensor. If nothing evident, swap the two O2 sensors side-to-side and see if the code follows the sensor (faulty sensor) or stays on Bank 2 (faulty wiring).

Remote possibility it is something like a plugged injector on Bank 2, but if that was the problem, you would still sense the misfire when the code set and the PCM went into open loop.

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