When I start my truck when it's been sitting for a couple hours and cold when I start it it starts out at 1500 rpm then 1200 then 1000 for a little bit then it sits at about 800 till its warm ish then when it's fully warm it idles at 550 like normal .

Is this normal? My parents 08 doesn't do that when it starts , I have to wait like 2 minuets, before I put it in drive, because if I do when I start it it bucks into drive because of the high rpms.

It's an 05 with 85k

 

1400-1500 is high idle. She should start and idle high but not more than 1500rpms for 20 secs and then settle down to normal idle which I believe is 625rpm.

 

What do u think is the problem?

 

Any ideas ?

 

There is no problem

 

It shouldn't insist on idling high to the point of bucking into gear. It also shouldn't take 2 mins for it to settle down.

First I would suggest starting it when its cold and using a stop watch time it to see just how long it's taking to drop. Possibilities that come to mind would be a dirty throttle body or maf sensor. Maybe a small vac leak or a throttle body sensor on it's way out.

 

My 08 5.4 would high idle at 1500 for 30 seconds or so then 1000 for another bit. Colder it was the longer it did it

 

I had an 03 with a 4.6 in it. I had a similar thing happening. When cold, even with RPM's under 1k, it would buck when initially put into gear, even in summer. After that. all was fine until engine got cold again.

I am not an engine person, so I brought it to my local garage.... very trustworthy...I know them. Anyways, I was told it was the oxygen sensor. Got replaced and all was fine after.

 

That is pretty strange I agree ...... So I cleaned the throttle body and it was pretty gunky I replaced the air filter and cleaned the MAF sensor with MAF cleaner still no luck ...... Back to the drawing board any other ideas ? I don't want to replace and o2 sensor that isn't bad because its not throwing any codes.

 

Look at the idle air control solenoid. When they get gunked up the valve sticks and causes the high idle and slow operation.