Ok. My 240 just went retarded on me two days ago and i have no clue why. Im kinda new to these cars so i need some help. Ok. I replaced my valve cover gasket and everything seemed fine. I drove about a mile to the gas station and it began to act up (spit and sputter). I drove back home and checked all my plugs and wires (just recently changed). Everything seemed to be ok. I tried to drive it again and when i would push on the pedal it would try cutting out and backfire and stuff. When I got it back home it would only stay running for around 2-3 minutes then cut right off. Is this a fuel problem or what? Please help me. Thanks

 

could be fuel related. check the fuel pressure, iirc it should be 43psi at idle.

 

You had your valve cover off, maybe a vaccuum line fell off.