Need a little help diagnosing this issue. Have a 97 old 88 with 3800 engine that starts and idles fine when cold but as it reaches operating temp it seems to be choking out. Has a new MAF sensor but if I unplug it then it will idle at operating temp just a little rough. I checked TPS and MAP sensors according to guides I found and they checked out fine. It does idle a little high about 1k rpm'*. Could the oxygen sensors be causing this?
If so is there a way to check them?

How did you check the TPS and MAP?

Did you check the IAC valve?

Used meter on both. There was a TPS code but when connected to the meter it had smooth resistance transition through full movement. For the MAP I only did a resistance test off vehicle between the contacts. I know that doesn't check the diaphram, could you point me to a guide to check that?
Took out the IAC and cleaned it but not sure how to test it. After that I ran vehicle until it reached operating temp but there are no new codes. Also noticed fans not running unless AC compressor is on.

What exact codes were you chasing? It'* also possible you are getting unmetered air in to the engine, as in a vacuum leak, bad MAF (aftermarket MAF sensors are notoriously bad on these cars).

Are you able to scan live data?

Unfortunately not, my scanner is pretty old. Is it something that can be done with a DMM? I have one that will read frequency.

And thanks to you and Mike, didn't mean to be rude in earlier posts.

Also, remove the vac line, to the f/p regulator and look for fuel in the line....if there, replace the regulator....

I had a problem with mine once with a stalling issue. After months of trying to narrow down the problem it ended up being a plug right next to your fuel rail and it connects the ignition module, Crank, and Camshaft to your computer. On my car the pins inside of that plug would get hot after 30 mins or so and it would lose contact and the car would die. Give that plug a good shake and see if your car spits and stalls like mine was doing. Can't hurt to check. Also, when the engine gets hot and up to operating temp spray your crankshaft sensor with cool water and see if the car runs right, if so you found your problem.

Matt

This is the plug I was talking about. just give it a good shake with your hand once the engine reaches operating temp. See if the car acts up when you shake it.