when i first start my truck up in the morning, it dies a few times before i can go anywhere. once it can keep running, it idles very high. my tach doesnt work, but it sounds like its running at around 2500 rpms. maybe even more. once i start to drive around for a few minutes, the idle goes back to normal and the truck runs fine. no codes. any ideas?

 

Maybe your truck ain't a morning type lol..... Anyone think it could be the throttle positioning sensor

 

I was gonna cast my vote for the IAC valve not working correctly....

 

My guess would be the idle air control valve as well

 

I replaced the tps and it didn't change anything. I guess I'll do the iac next

 

You can try cleaning the IAC out with some brakleen or electrical cleaner and see if it helps then you know where the problem is. I did this on my Aerostar and it ran fine for another year or more. If it just improves your problem at least you know your on the right track.

 

This isn't normal cold starting? I've changed both the IAC and TPS and the cold starts still put the truck and a 2,000 rpm idle for about 30 seconds to a minute and then drops to 1500rpm for another 20 seconds and the 1000rpm normal idle.

 

my truck will do this for several minutes. this morning it was worse than ever. it was practically floored without me touching the gas pedal. it seems to go away after driving. the truck seems to shake at idle much worse than usual as well.

 

you need to look for a vacuum leak put a gauge on it have someone else start it a eradic needle shows a leak

 

wheres the best place to hookup the guage?

 

An erratic vacuum reading does not necessarily indicate a vacuum leak. I would suspect a valve problem if the vacuum gauge was fluctuating.

I have never used a plain vacuum gauge to diagnose a vacuum leak. Spraying the vacuum lines with carb cleaner or propane have been mentioned before, but I find using a hand held vacuum pump, that also does have a gauge, to test each vacuum circuit will uncover a vacuum leak very quickly. It will not find vacuum leaks caused by intake gasket, cracked manifolds, etc.

 

i got a chance to fool with the truck when i got home from work today. i replaced the iac and i found a broken vaccume line. i got everything together and now the truck is running mint. it idles much smoother and doesnt die when i first go to start it. one of the hoses that comes off the throttle body and into that Y fitting was broken. thanks for all the help!

 

Thanks for the update, great to hear you found the problem!