Changed fuel pump assembly, new PDC, AIC, TBS, MAP sensor, cleaned throttle body, new alternator, good battery, CPS and CRS check good. New plugs, new cap and rotor. Still just starts and runs erratically for up to 10 to 15 seconds and then stalls. Good compression. No vacuum leaks. No security system. Please help! All ideas welcome.

 

Bad gas maybe, or dirty air filter. Did you check the coil?

 

Air filter is clean. Coil is good. I will try replacing the gas. Thank you.

 

Recheck distributor for proper install. Even the most amazing seasoned mechanic doesn't do everything perfect every time (finger pointing at me).

 

What engine and year?

Can't hurt to get a fuel pressure gauge on the rail to verify you actually have good pressure. Do you have a security light blinking or anything like that?

 

Was it running fine then started running bad or did you work on it then it started running bad?

 

Was the battery disconnected for a while? I don't know why, but if my PCM isn't supplied voltage full time (before I put my new Optima Yellow Top in I was having battery issues) the PCM would forget "how to run" I don't know of a better way to explain it. Even hooked up to very good jumper cables to another truck that was running (so very good strong connection with high voltage and amperage) it would start and then die after a few seconds. I had to go drive it around two footing it the entire time to keep it from dying. After about 10 miles or so it would relearn itself and run just like it always has.