Well I really dont know where to start, but it all started when I got my intake, plenum, ect.. ported and polished. Well back last summer I had the problem with the SES light coming on, but that got fixed because I purchased the updated PROM chip for 86 TPI's. All was well until I had the porting and polishing done. Since the parts came off, then were reinstalled.

Well now when I start my car up in the morning (cold) It will be fine for about 30 seconds of driving down my street and then..... The SES light will come on and the car will Hesitate like no tomorrow! I mean like 5 seconds after I hit the pedel the car will then go. However the car gets better and better as it warms up but the light wont shut off. The light wont go off until I turn the car off and then go back to driving it while it is still warm. But still the light will occasionally come on and off at will for a few seconds at a time, but no problems will accompany it. It keeps reading as the O2 sensor, which I have replaced now with a Delco, Bosch, and some other name as well now. I know for a fact it is not the actual sensor.

The garage that worked on my car for the porting/polishing said that it might be the IAC motor?? Please someone help me! I would like to fix this issue before she gets put away for the winter

 

Do you have acess to a scanner like diacom or moates software or anything?

Also have you checked the 02 wire and made sure its got a good connection from end to end?


The weird thing is that the 02 sensor isn't used while your car is cold and shouldn't trigger a light 30 seconds into driving (depending on whether or not you let the car warm up)

If it idles just fine I wouldn't suspect the IAC.

 

I do not have access to a scanner. However how do I check to see if the wire is good from end to end? You mean from 02 Sensor to Pigtail connector or from pigtail connector to ECM? Thanks for the response!

 

exactly, get a multimeter and ground say the engine bay side and then ground the negative electrode to the car, and the positive to the wire make sure you can complete a circuit ( no breaks in the wire). Then probe one end of the wire, and the chasis just to make sure it isn't shorted.

It possibly wont be it.. but it beats throwing sensors at the car untill it works. Thats why a laptop and craig motes software is such an increadibly usefull tool, just plug it in and you know your problem.

 

Be *very* sure you have the O2 sensor unplugged when doing this. The voltage put on the circuit from a resistance test is enough to damage the O2 sensor. Check the harness wire all you want, but don't test resistance across the O2 sensor.

 

Good call

 

Thanks guys I'll try this tonight with my friends. I'll let you know what happens.

 

ttt

 

Have you changed the fuel filter lately?
Also might want to have the pump checked for pressure and flow.