alright,i have a 97 f150,4.2 v6,and i suspect the fuel pressure regulator is bad.how do you test it?i already pulled the vacuum line off and there were no signs of fuel leaking through it,so whats next?runs really rough,cats glowing,took off cats to see if the were plugged and it seemed as if there was unburnt fuel coming out of the manifolds.compression test showed great pressure in all cylinders and the plugs all looked soaked,carboned up like there burning way too much fuel.pleeeeeeeeeease help!!!!

 

Install fuel pressure gauge. The pressures should be around 42-45 with key on engine not running. The fuel pressure should be around 30-36 psi with engine idling. If regulator is dumping fuel, the pressure will be really high.

 

appreciate the info.got 40 psi with KOEO,and at idle i got 37 psi steady.it barely runs,i have tried a new pcm(used),coil pack,did the compression test,fuel pressure test,new plugs and
i have tested the cam sensor for the switching cycle that signals the pcm to start the injector pulse sequence.whats next???

 

Have you checked the ignition system to see if there is enough spark to burn all the fuel? Had a Crown Vic do that aand it was caused by a bad coil.