Issues with my 1998 F150 4.6 2 wheel drive 85k miles. It started with a check engine light and it running like crap only while driving. Seemed to run well at idle and sitting still. I checked all the plug wires at the spark plug thinking since the 4.6 liter had issues with leaking coolant from the manifolds into the spark plug galleys no issues there. I suspected coil pack issues so I took it to and auto parts store where they hooked it up to their scanner and got the code "pressure control Solenoid A short circuit" no cylinder miss fires. Then took it to a transmission shop where they replaced that solenoid put a new filter on and replaced the tranny fluid. when they test drove it ran like crap and threw the same code. they checked the electrical connection at the tranny and checked the wiring and came to the conclusion that it must be the ECM. They replaced that and it ran great for about 10 miles when it quit on me the coil packs were so hot you could barely touch them. there was no spark and the ECM smelled burnt. I then replaced the coil packs and put the old ECM in and the truck ran great for about 25 miles when the check engine light came on. Figuring it was the ECM I replaced it with the new one that the auto parts store replaced under warranty. The truck wouldn't even start! ERRRRR. I then put the original ECM in and it started with no problems. and that's where I stand now. Any help would be greatly appreciated.

 

You need to boil this down a bit to the most important items.
What is the code? not your description of it..
What does running like crap mean specifically.
Don't add anything else.

 

So did you ever remove a spark plug to check the gap? How many miles since they were changed?

 

sucks but sounds like a short somewhere
check for continuity to ground at ecu and sensors un plug every sensor check for shorts
look for wire issues
look for corrosion at every connection
test every pin
i have fixed the ground at the top of my tank for the pump
i have fixed a broken #10 ground for my drivers door controls... was cut 99% worked only if door was shut
fixed ground to tps
it is just the age ...20 years is a lot of wear n tear
i would not try to plug in a new ecu until I was sure there was no shorted wires