[swampfox44]

I recently bought a 1997 F250HD 4x4 w/5.8L. The truck has 144,000 original miles. PCM went out about 2 months after I bought truck. It went into Failure Management Mode and wouldn't clear.One code only code shown was IAT sensor.But,after replacing it,still didn't clear.Did pin test and PCM showed bad.
Well,now truck seems sluggish with new PCM.Checked timing,it's dead on 10* base,air filter is new,I did a vaccuum check to see if any backpressure problems with exhaust and everything checked out fine.
Truck seems to have power when cold,but,after reaching normal temp,it's a slug.Lugging up hills.I pulled out the new IAT as it was an Autozone unit. I put the factory IAT back in.Haven't had a chance to drive it yet with old IAT.
I do know my fuel economy has dropped from 16MPG to about 10MPG.
Also,when I leave truck idling for about 5-10 minutes,it will idle up,sputter and shut off.Turn key and it will spin over but not start up.After sitting for about 15 minutes,it will start up just fine.
Anyone have any clues? Suggestions?

Thanks