Hello everyone! I was wondering if you guys know how to test an O2 sensor that has become "Lazy" in other words, contaminated or just plain outlived it's service life? I too, have a stumbling issue, after the car is at operating temp, especially after coming off the freeway or at a light. ('94 Vette) I can't tell you when or if the opti has ever been replaced, probably not and the car has 127K miles on it. Probably due for one. I did find a badly corroded coil wire, replaced that and found the number two sparkplug wire was arcing at the plug boot. fixed that, I also cleaned the MAF sensor and MAP sensor just to be sure. Replaced the ICM module and I also replaced the ECT sensor because I know it's the sensor the PCM uses for fuel adjustments, all this helped, but still have a stumble at temps. and I have not found any codes at all......any ideas? I heard that some guys are finding their throttle body bolts loose, have yet to check those out. any help would be greatly appreciated!
Thanks!
Ben Smith

 

Did you figure this one out? I have a very similar situation. Just replaced the coil wire due to corrosion and have had a miss under load for a while. Really wondering about the O2's, but I have no idea how to test them first. I don't see any arcing around the wires at night, just some that looks like it is in the MSD coil.

 

So I am having the exact same prob with my 95 Z28. I've changed the fuel filter.plugs. starter. Module.coil.had my alternator checked passed five times. Brand New battery. Had my Opti checked runs the tester light occasionally jumps but not sure if that's a thing to worry bout. When i was changing out the module n the coil I accidently pulled a tube out of what I am assuming is my air intake it has a cap on it n is connects to a bunch of smaller tubes it sits right next to the coil behind the air mass flow n filter. I'm just freaking stuck. My card won't run the OBD1 reader not sure why my fuses are all good n so r my relays. Help please I really don't wanna have to gut this car n sell her for parts but it seems to be going this way. Trying to fix one thing then another thing mysteriously breaks like my driver door lock.

 

I would suggest you restate the specific problems you are having. Are they identical to “tbenedict” who you quoted? He indicated his problems were “similar”, but appears to be responding to a post complaining about “slow O2 sensors”. Or are you referring to the specific problems in post #1- “runs perfect until it warms up then stumbles a lot”?

Given this is an 11+ year old thread, might be best to start a new thread. In any case, we need more info in order to help.

What “OBD1 reader” are you using, and what method are you using to attach it to your 95’s 16-pin DLC connector?