after replacing the 4 o2sensors, they were bad on the dtc's tune up and even new battery, getting coverter code now. Po420. also having a problem with keeping fuel in the system after it sets and cools down. i've squirted a little gas down the throat and it fires off. when i floor it on the expressway to pass it almost dies out then slowly speeds up. if i gradually apply the gas it goes accelerates normally. any ideas ( fuel pump was replace jan 05) new plugs, wires, cap, rotor, ign coil and battery jun 06

PO420 is catalyst related correct?

Sounds like you have a bad cat if you've replaced all of your oxygen sensors

Well the cat problem is so so now. i cleared the code and it hasn't come back. the original proble ( won't start after setting overnight ) is still there. over that last three weeks i have put in plugs, cap and rotor battery 4 o2 sensors, fuel filter, all new. this truck will kick butt now on the passing gear. but this dang no start is th ekiller. it will start with no problem when i put just a little gas down it's throat. any suggestions anybody

You either have a fuel pump check valve leaking or a fuel pressure regulator check valve leaking. If you have a fuel pressure gauge, hook it up to the test port & see what the fuel pressure does when you shut off the vehicle. It will probably fall fast based on what you have said here. If it does then pinch or block the return line & try it again. If the pressure then stays up, then you have a bad regulator. If it still falls, then you have a bad fuel pump.

Im havin a promblem with my escadle gettin fire to it.. we checked the fuel pump an the lines...everything seems to be ok..it will fire when u poor a lil gas down the throat but only for a sec any idea's

Is the fuel filter clogged?