TP sensor/idle problem?
 

my 87' 2.3L EFI is idling bad... revs up and drops down, revs up an drops down, ect... if i unplug the TP sensors, it idles just fine. i've check the TP sensors with a volt meter and it checks out good. even still i went and got a new one, which i think was defective because it read 5.01+ volts at WOT and at an idle. never droped below 5 volts. so i put the old one back on. and with the old one back on it idled fine for a few hours then starts idling bad again. also it usually (not always, but usually) idles fine in the morning when its cold. then after it warms up is when it seems to start idling bad. (unless i unplug the TP sensor then its fine.). could the heat be messing with the TP sensor or somethin? whats the problem here?

also when the idle drops down it seems to miss really bad. but only when the idle drops. and when i push the gas, unless i floor it, it bogs down really bad. again if i unplug the TP sensor it runs fine.

It's unusual for a bad TPS to cause a surging idle all by itself. Usually, that only happens as you try to move the throttle. Heat can affect any electrical component, and if you want to see if that's the cause, use a hair dryer to heat it up. I would try checking the other wires for problems.

BTW, which wire did you test your new TPS with?

i checked the green wire.

i know it shouldn't... but it does. cuz if i unplug it, it runs fine. when i check the green wire WHILE its running at an idle (when its idling ruff) the voltage is going up and down with the idle. shouldn't it be steady since the butterfly in the TB isn't moving? when the engine off and key on, it reads a steady voltage. maybe a bad input voltage to the TP sensor?

What are you setting the TPS at(Key on engine off)?

.9V - 1.2V

testing with a digital voltmeter. positive to the green wire, ground to body. does it matter if i set it when its cold or do i need to warm up the car to normal op. temp.?

Did you check the IAT?

Any codes? I have no experience on the 2.3L. Also check your MAF. My car idled like crap then I change the MAF, Coolant Temp, and TPS sensors it idled much better.

whats the IAT? there were no MAF's on 87' 2.3L EFI's

Intake Air Temp sensor.

I'm not familiar with the Non-MAF cars. Can't really help :(