97 ranger rough idle

[BassRanger]

My ranger 4.0L V6 has been idling rough and dieing when stopped. it would clear up if i rev at about 1000rpm but wont idle itself. i was told it was upper manifold gasket so i replaced the set upper/lower/valve cover gasket since valve covers were leaking and intake was coated with gunk (crankcase vent hose had been off for few years apparently) i clean everything as best i could assembled and now its worse. IAC unit seems not to move ( i removed from intake engine revs high no movement in IAC with it mounted engine revs high IAC off/bypass hole blocked engine dies instantly thought i knew when i started now i have no clue any ideas would help greatly

 

[blacksnapon]

Start with the IAC motor. Those are prone to failure. Vacuum leaks and egr valve sticking are another couple of possibilities.

 

[BassRanger]

egr sticking open? its not supposed to purge cold or at idle maybe purge solenoid?

 

[blacksnapon]

egr sticking open? its not supposed to purge cold or at idle maybe purge solenoid?

Essentially, egr is a controlled vacuum leak.

 

[BassRanger]

truck also backfired and did not before i changed gaskets a vacuum leak would cause backfire maybe failing EDIS pack or cam position sensor cause backfire and vacuum causing idle problem leaning on IAC stuck open