ok... about 4 months ago, I shimmed my FPR, and it made my truck lose power and bog down, so I removed it. Ever since, my idle has been really rough, and for the last couple weeks, it has shuddered (more like a cough) at lower rpms, especially when the engine is cool. Last night, I thought it had finally gotten as bad as it could get, because it started acting up even worse. I changed a push rod that was bent into an s-shape, and it's back to the rough idle (abnormally rough, even with the 10k removed) and such.

I realized today that it smooths out perfectly when I unplug the ICP. It's not the sensor, because I tried a brand new one, and no change. Should I leave it unplugged? I'm at a loss here...

 

If it is warm & cold ,,may have a sticking IPR ...
Some have had luck cleaning it ,,but not many...

 

Go with a electric fuel pump.