Well guys the car has been surging at idle every so often and has always idled rough sometime better than other times, but it seemed to missor studder at idle or low rpms lately so i check ed out the IAC and it looked shiny and preety new. Then I looked at the TPS sensor, it was reading at .75 at idle so I thought wow this is bad and loosened it to find out HEY it is not adjustable, so after playing some with it I got it down to .72 until I could get the new sensor, it seemed a little better. So I get the new AC Delco sensor today and throw it on and really there is only one setting you can set it at. So i take a reading and it is now at .85 at idle! It seems to idle lower but still around 650rpm and maybe run a little smoother, what in the hell is going on?

 

Start looking into tune-up parts. You may need to reset the IAC or at least clean out the passages.
The non-adjustable TPS's came on our later cars. The ECM self zero's them. There's no need to adjust the TPS on them. I don't know the cutoff year but my 88 is adjustable and my 92 is not.

 

so even though on the meter it is reading .85, its actually ok? The IAC looks beautiful and i celaned the throttle body until it shined. I has new cap, rotor, plugs wires, 02 sensor and now tps. What else should I look into...would the coolant temp sensor be a threat?

 

anyone?

 

As long as you have a full smooth sweep, voltage-wise, on your TPS then that .85 setting won't be a problem.
Possible coolant temp sensor but I would concentrate a bit more into looking for a vacuum leak.

 

On your TPS issue, you also want to check the idle screw for the throttle on the TB. If the factory cap has been removed, and it's been adjusted before, it might be holding the throttle plates open too far at idle, which could cause the high TPS setting at idle.

 

I thought the same but the cap is still in place. what else could cause this really rough idle?
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