i have a 93 f250 with a fuel injected 7.5l (460) in it. every time i start the truck it revs to around 2700 rpms for a few secs then drops to 900 and its misfiring a little at higher rpms while driving. i thought the high rev was the IAC valve so i replaced that and the problem is still there. any suggestions?

 

Hard to say, but I would do a tune up. Mine does a similar thing on the front tank, I think (or know rather) that the fuel pump is getting tired, It will pum a little bit of fuel from the rear tank to the front so the check valve is bad, but change the fuel filter, they get neglected for some reason and that causes more issues down the road.

 

ya i just did the fuel filter as well, do you think it might be starving its self out of gas? i put a fuel pressure gauge on it and its got good pressure.