Ok i have a 08 f150 with a 4.6

I used the search function im not new to forums so i dont want to hear that haha.

Ok for starters it has been to ford and they said no misses at all it runs fine.

It starts up great but once it warms up it starts the rough idle. Its just enough to shake the antenna and rattle my loose mirror.

I have cleaned the MAF sensor.
Replaced intake manifold gaskets because of coolant leak.
New auto lite double platinum plugs.
New fuel filter.
New air filter.

My next thing to do is use some throttle body cleaner.
Replace pcv because it has some oil around it. Could be a vacuum leak.
And maybe replace egr too.

Any idea. I like the truck just want it to idle right.

It drives great at speed and i get between 14 and 17 mpg. So it seems alright. Ran injector cleaner and put good synthetic oil in with a motocraft filter. Any help would be great thanks.

 

It only starts running rough after engine warms up at idle?

 

Yes that is right. Its slightly rough at first but really bad when its warm. Hope that means its simple to fix.

 

There's a difference between the truck itself shaking and the idle being bad.

You need to find out which it is; is the truck shaking or is it a bad idle? I ask because your engine and idle could be fine. Something like a bad motor mount could be causing the shaking...........

 

I would check your oil pressure when it get hot see if your dropping below25psi. Since you have 08 if under 60k see if your powertrain warranty is still there.

 

It had 90k so way out of warranty. How do i check my oil pressure? It is past half way on the dash.

 

I have thought that my self too. How do i check motor mounts? Its one thing i have never done.

 

SEA FOAM in the break booster line first

 

Clean the throttle body... And the MAF... And disconnect battery and do the relearn process.

 

I did the maf last night and disconnected the battery. It seemed better but still sucked. How to i clean the throttle body? Do i have it off and blow it out with choke carb cleaner? Or just try the stuff you spray in while its running.