I got a 1999 ford expedition and these are my issues: filled up with gas drove about 200 miles and expedition started to miss very bad and check engine light was flashing. Started with new spark plugs, didn't fix. when I had it scanned no codes came up except the on for the check engine light, but the left bank down streamO2 censor was not as responsive as the others so I replaced it. I have checked the injectors and the COP's (coil over plug) they where good .The fuel pressure is 35 psi, the fuel pressure regulator is making a differance when dissconected. The tank was drained to within about 1/16 of a tank then filled with 91 octaine and lucas injector cleaner and fuel conditioners was added.

If anyone can help
Thanks: Crazyman

 

Sound's like a vaccum leak.Also if the check engine light was on you should have code's how did you check them?

 

It was checked with a vantage computer by snapon. Mon. I will download computer on the expedition to check if any more codes are pressent.

Thanks for the help: Crazyman

 

yes if it starts to run rough check the pcv valve and you will see a hose coming off of it make sure that the line doesn't feel all mushy and seem like it will stick together then just take out the old and in with the new.

 

just make sure you reconnect the line to the fitting just behind the intake manifold around the back tight space to fit your hands back there but not too bad.