exactly what i was afraid of

[BassRanger]

I tried to fix it and made it worse its a 4.0L V6 EFI with distributorless ignition what would cause backfiring Cam position sensor or EDIS pack maybe it had a rough idle then i took the whole intake off and cleaned it upper/lower/throttle body and replaced gaskets now it either revs high or up and down (took IAC off left wires connected revs very high, IAC off wires connected plugged IAC hole it revs up and down or just dies) no movement from IAC mechanism in either case unplugged mass air before new gaskets would clear idle problem but has no affect after new gaskets could IAC stuck open cause backfiring

 

[chubyboy]

IAC would not cause backfiring, timing would...

 

[smokey]

Sounds like you introduced a vacuum leak when putting it back together causing the idle problems.
When does it backfire? at idle or at higher rpms, etc
A bad coil pack is one of the main causes for a backfire in these engines.

 

[m78]

Thats an old thread.

 

[smokey]

Yeah it is never looked at the date on the first post.

 

[BassRanger]

Sounds like you introduced a vacuum leak when putting it back together causing the idle problems.
When does it backfire? at idle or at higher rpms, etc
A bad coil pack is one of the main causes for a backfire in these engines.

sorry i didn't what i found but u called it dead on when i put new intake gaskets on i tweaked the egr valve tube which put a large crack in it. rather than spending $200 for the replacement part a $5 tube of exhaust repair puddy did the trick