Sorry for another non 3rdgen question but Ive got an 88 f150 I'm tinkering on. The pu is a FI 5.0 and it has a ton of problems but I just need one fixed for now. The truck idles @ 3k or so the second it starts and stays that way. I checked codes nothing special, checked the IAC motor, it was bad so it was replaced and new one tests good. If I unplug the IAC the idle goes down but its not driveable of course, the same thing with TPS. I cant get the tester leads on the tps (stupid fnord). I can hear a big vacuum leak with the tps or Iac disconnected so I'm betting the plemium gasket is damaged. Would the plemium gasket cause it to idle that high? I know It could cause itto idle high but over 3k is a bit much.

Any suggestion would be appreciated.

Happy new year!

 

A vacuum leak could cause a high idle, but I've never seen a 3k one from that. I knew some kid with a 3k idling 5.0, but I don't know how he resolve it. It was a MAF car. He had changed the IAC, TPS, and MAF. Better fix the leak and go from there. Whatever the case I think it's best to just put her down.

 

Is this the 300-inch inline six? They have a really wierd TPS and IAC system, and adjustments can be a PITA.

 

Its a 302. Would be nice if it was a 4.9 I-6 (IMO the only good engine fNord built).

This thing is bugging me Ive been reading in my spare time today trying to figure this turd burgler out but nothing conclusive of course. I'm going to change the gasket and at least test the TPS, I dont think the MAF would cause a high idle problem but one never knows.

 

Update.. Still nothing!!! I changed the gasket then started it up nothing changed except I was able to pull a code 63, TPS low voltage so I changed that and eliminated that code. I did drive it a little in the parking lot, when you put it in gear the idle does drop to a normal idle but it lacks power where its not driveable and it does go back up to 3k when put in park. I rechecked all the vacuum lines and ground wires all intact, even called in a couple favors from some other mechanics who told me to try what I already did and were as as I am. The snap off guy claimed to be bringing in the replacment E.A. today but of course he dident.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I HATE FORDS! !!!!!!!!!!!!!!!!

damn now I have to go put a clutch in an escort.