So I have a 93 z28 and it is having poor idle and stalling sometimes as well as misfiring. Other times it will drive completely normal. Sometimes it will die when driving but will turn back on after about 3 seconds of just rolling and giving it gas. I’ve already changed my fuel pump due to low fuel pressure and the egr and air are deleted. Not tuned out though. The only codes I have are code 26 and code 63. Does anyone have an idea of any test I should do or what could be the issue. My car also started blowing blue smoke but I believe that is to due with the car current having no mufflers on it. Basically being straight piped.

 

Did you check the circuit on the Bank O2 open circuit (DTC 63)?

Are you running open collectors on the headers (no mufflers)? That can really screw up the O2 sensor readings, and cause the engine to run excessively rich. “Rich” is generally black smoke. Blue smoke is generally oil. Have you checked the plugs for fouling, wet fuel, oil?

Not sure on the stalling…. ICM, Opti…. But should set codes.

 

I just looked and realized my passenger side o2 is unplugged. I have a new one I’m going to put in anyways. The exhaust is cut right before the axle but has no cat or anything. I had to remove the exhaust when dropping the tank and haven’t had time to have it welded back on. The car when idling drops to a really low rpm and sounds super choppy almost cammed then I’ll I’ll pick itself back up and rev up to around like 1500 and hold it for a few seconds. Then idle normally until it does it again. What confuses me is the fact it’ll run fine one day then run has the next.I have not checked the plugs yet but it will be one of the next things I do.

 

One possibility is to download the free Scan9495 software (works on 93 too), get a cable, and scan the ECM. You can run a data log (records sensors and critical ECM parameters) while driving, and I can take a look at it to see what is going on.

https://www.camaroz28.com/forums/com...95-lt1-874306/