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TPS or IAC?


miamibob
04-11-2011, 07:34 PM
Hi All,

Got an '87 GM that has a "slight up/down idle" when first starting. Only lasts a minute or so and then is fine. Sometimes a slight stumble from a stop. Likeliness culprit be a TPS or IAC?? Car has a little over 121K and have had it from brand new. Never remember changing the TPS but did the IAC a couple of years ago. Forgot to clean out the ports before install, though. Boy was that dumb!! Let me know your thoughts!! Thanks....MB

Blue)(Fusion
04-12-2011, 09:17 AM
Use a multimeter to check the resistance of the TPS as you move it.

It could also be a fuel pressure problem.

way2old
04-12-2011, 06:33 PM
There is an Intake Air Temperature sensor on the drivers side front that will cause the problem you describe.

miamibob
04-12-2011, 08:16 PM
Where exactly is that sensor located? Looks like it is threated into something and has an electrical connector but where is it screwed into? Thanks....MB

Blue)(Fusion
04-13-2011, 01:10 PM
Not sure about on a 5.0L, but on my 4.6L it was located on the top half of the air filter box.

miamibob
04-13-2011, 05:52 PM
Yes, I had a '93 and also currently have a '95 and on the 4.6L, that is where it is. Didn't even know a 5.0 has one? Got to check the official manual as Rock Auto does list one for the 5.0.....MB

way2old
04-13-2011, 06:08 PM
Look on the intake between 5 and 6 cylinders. it should be licated there if I remember correctly.

miamibob
04-13-2011, 06:11 PM
Hey Good Buddy! Is that Passenger or Driver's side?? MB

way2old
04-13-2011, 07:01 PM
Drivers side. Those little sensors are suspect to carbon build up on them.

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