I just changed the alternator on my 2003 Excursion 5.4 Triton. When I started it. Fired right up but immediately died. Will stay running if I keep the accelerator pushed down. But cuts out and backfires. Changed fuel filter with no improvement. Any ideas?

 

Either a disturbed vacuum line came off or is leaking or the AIC automatic idle control on the throttle body is sticking or?

 

Moved to the 5.4L Modular forum.

Stewart

 

Sorry new guy here. Didn't know where to post.

 

Thanks I'll check those later today and post back.

 

No worries. We dabble in engine/drivetrain too in the Ex forum, but this is a very specific engine problem and I wanted to get your problem the most exposure possible.

Stewart

 

Are you sure it is "AIC"?
Our 2003 5.4L has an IAC (Idle Air Control) valve.

Check all the vacuum lines, particularly the large PCV hose and elbow.
The hard plastic tubes can split, too.

 

Agreed with probable IAC & vacuum leak as primary concern.
I'd add that cleaning the MAF sensor could not hurt either, as well as, checking fuel pressure