ok i have an 88 f150 4x4 lariat that I just put a new tranny it. once i get it started up (usually with some starting fluid) it will idle fine for a min or so and then start to idle real rough to the point where the whole truck shakes and then just dies. not sure why. I took the iac vavle off and cleaned it real good but it made no difference. any other reasons why its doing this? IT has a 5.0motor. Thanks

 

Disconnect the wiring harness from the IAC with the engine running. If there's no change in the idle, the IAC is bad and needs to be replaced. If it starts bucking and sputtering worse, then the IAC is fine.

But before you go too far with anything, I recommend that you go to Ford Fuel Injection How To Run a Self-Test and pull the codes. Even if the check engine light isn't on there can still be codes stored.

If you're having difficulty counting the blinks, these code readers are cheap and very easy to use. I picked mine up for $30 at O'Reilly's. 3145 Digital Ford Code Reader (1981 - 1995) - Equus Code Scanners

Good luck and let us know what you find.

 

ok so i checked the codes and if i did it right it seem to have came out code 32 which was the egr not controlling. A bad egr vavle can't be the problem can it? it seems to have gotten worse. it will barley start up with starting fluid and now wont even stay running. could a bad egr valve be the cause of this?

 

Yes, a bad EGR valve will cause the symptoms you described. If its sticking, the engine won't be getting the right amount of the air with for the amount of gas that its being given, causing it to idle really badly and even shut off. Most egr valves don't actually go bad unless they're vaccum, if its electronic, you have a good shot of cleaning it if you want to save money. All you have to do is clean the inside real good and then push up on the rod manually and clean that as well to make sure the rod can move up and down and its not jammed with carbon build up.