So I swapped a 1999 5.4 into my 1997 expedition chassis and after completion of the swap the engine now over revs upon start up it will rev up to 2000 rpm then slowly in steps back its way back down to normal idle just below 1000 rpm so far to try to correct it i have:
replaced all large vacuum lines
Checked for leaks (vacuum gauge check at a port on the back side of plenum) at my intake manifold
Cleaned my MAF
Cleaned my IAC (didn't know how to test it)
I am stumped on where to go next any help would be much appreciated
replaced all large vacuum lines
Checked for leaks (vacuum gauge check at a port on the back side of plenum) at my intake manifold
Cleaned my MAF
Cleaned my IAC (didn't know how to test it)
I am stumped on where to go next any help would be much appreciated
