Hello, this is my first post on this site, great site by the way. My problem is on my 1995 ford f-150 4x4. It has always run good since I have had the truck even with 194000 miles on it. A couple of weeks ago it starting running bad just out of the blue. Now when I start it in the mornings and after work it starts fine, idles up for a few seconds and then it idles down to around 300-500 rpm's and shakes and jerks if it doesn't die and then it idles back up and stays around 1200-1300 rpm's. It runs fine after all that but it never idles back down like it supose to. Does anyone know what might be causing this? Any help is appriciated. THANKS.

 

I'm suprised none of the fuel injection guru's have answered your post by now. Here's my suggestion, It's most likely the IAC (idle air control valve) they can get sticky. If you feel like spending a few bucks just grab a new one there pretty cheep. If not, you can clean it, it's pretty simple. It's bolted to the side of the throttle body, is aluminum, and attached with 2 bolts. Just take it off and clean it out with some brakeclean or carb cleaner. Once you get it off it's pretty easy to see how it works and clean out.

Hope this helps good luck.

 

I agree with the IAC being the problem. There are other things that could cause it, but this is the most probable.

 

Does it idle funny when do a warm start? IE you just ran into the store

 

Thanks for the info Opossum. I did check it and it doesnt seem to be working at all, and some how in the process I broke it and my truck started idling high so I made a restrictor plate to put between it and the throtle body, idle is good again,I drilled two small holes in the plate for air, but it still does the same thing.

 

Hey StealthWyvern, so far it only does it when I first start it and it's cold. But I did notice that when i'm driving at speed and let off the gas completly the rpm's ocillate up and down for a few seconds then it levels out again, Thanks

 

Did you replace the IAC with a new one?