erratic idle

[katt68]

my 92 ex 4.0 idles good but it kind of goes up and down from about 1000rpm to 800 rpm. any ideas?

 

[TPLYNCH]

IAC needs cleaning/vacuum leak/intake manifold gaskets need tightening Take you choice.....

 

[Texan01]

my 95 does it too, must be a Ford thing since I've cleaned the TB, the MAF, the IAC motor, and the passages in the intake, tightned the upper and lower intakes, and checked for vacuum leaks. Might be EGR bleeding past the seat, might get bored one day and pull it off and clean it up.

 

[EliteConcept]

maybe fords just never idel right, mine will idle great one day and horrible the next.....or go several days ....just depends.....