92 f150 302 4X4 aod

I have checked through all of the forums and have yet to come up with the solution to this problem. The truck runs fine on a cold start and runs down the road the way it should. Once it warms up it starts missing and causes the truck to shutter. It will also sputter pulling away from a dead stop, once it is warmed up (does not do any of this from a cold start). I have scanned it quite a few diffferent times and get no codes. i will list what I have done so far and maybe you can help tell me what I missed!

replaced all vacuum lines (verified routing about 10 time)
replaced EGR Valve, EVP, EGR control solenoid (tested new parts all good)
replaced TPS (tested TPS and adjusted it properly)
replaced Idle Air Control Module
replaced MAP Sensor (tested good)
replaced Ignition Coil (tests good)
replaced Ignition Control Module
replaced plugs (autolite Platinum) gapped properly
replaced wires (have been routed properly to avoid cross fire)
replaced air filter
replaced O2 Sensor
replaced Engine coolant temp sensor (tested good)
replaced cap and rotor (bronze conductor set)
ran injector cleaner through system for last 5 tanks of fuel
checked fuel pressure at rail. 38 psi engine off, 32 psi engine running, 40 psi running w/ vacuum line disconnected.
checked upper intake plenum for leaks, could not detect any
switching tanks while driving does not affect this at all


The motor is a fatory long block crate motor installed by ford about 2,000 miles ago. Just paid them $90 to put it on their machine, for them to tell me that they have no idea what the problem is. Gotta love those dealerships!!

Anyone with any suggestions, ideas, anything would be greatly appreciated
Randy

 

forgot I replaced the fuel filter also

 

how old is your exhaust? could be a clogging cat or muffler....

does the engine overheat at all?

it sounds like you covered all the other stuff, idk but i knew of a friend that had a cat goin bad, it start fine then as she drove around it would lose alot of power and almost stall on her, one day they called me to help, they were stalled, i openedthe hood and the headers were bright orange from the clogged cat lol....needless to say the car didnt last long after that. good luck!

 

I did bang on them to see if the baffles were loose, they were not. Assumed they are good since it didnt throw a code

 

use a vacuum gauge to test back pressure.

which temp sensor did you change?

the one on the thermostat or the one on the lower block?

 

changed the temp sensor at the thermostat, I'll have to check to see. I dont believe there is one on the lower block

 

That is the right one for the Computer.
The other temp sensor on the intake behind the distributor on the drivers side is for the gauge.

 

checked vacuum from intake. stays at about 18.5 hg at idle, 15.5 hg at 2000 rpm. Test says vacuum should drop to 0 then recover. i could not get this to happen. it would just drop to 15.5, then head back up to 18.5 after releasing the throttle

 

that is the one for the computer.

the one on the block is for temp gauge and you do have one.

 

doesn't sound like clogged exhaust.

 

It was also missing like crazy from idle til I got up to about 15 1600 rpm. then it clears up

 

i don't like the plat plugs.

they never seem to last very long.

have you read them lately?

 

I pulled them all out last weekend and they were all gapped properly, and spotless. I remember having an issue using them in my one Tbird, it just didnt seem to want run right with them. That was a constant miss though, not just when it warmed up

 

i would try a set of motorcraft coppers just for fun.

 

I might just try that. You dont believe that a cat could be clogged? The truck only has 98000 on it, and I replaced the exhaust from the cat back, so I know that is all new. Only things I havent replaced were the cats, Injectors, Ignition pickup in the distributor, and the fuel pressure regulator (cant figure out how to get that darn thing off with an allen wrench) Think I need longer skinnier fingers