Mis-fire after car sat for a week?

[kyledude351]

Car was running great before my trip to Mexico. Got back last night and went to pick up a friend, car would missfire going up the rpm range, and shot an abnormal amount of flames.

So far:

- Cleaned air filters (previously had K&N oil on them)
- Cleaned mass air flow sensors
- Checked all intake piping and connections
- Checked all spark plugs (cyl 4 had some soot)
- Did compression test, 140psi across the board

Anybody have a similar issue? It just baffles me that the car was running great just a week prior.

[Skym]

- Checked all spark plugs (cyl 4 had some soot)

Soot on tip of spark plug = coilpack leaking. The coilpack can crack on the side under mounting bracket on both sides (age + heat + seam = leak) and the charge leaks onto mounting bracket (grey marks on side of coilpack).

Coilpacks usually fail due to incorrect sparkplugs (heat range or sparkplug gap) or age (change all of them at 100,000km).

Also check cylinder 5 as well, as usually when cylinder 4 coilpack goes, so does 5 not long afterwards (happened on my car).

Edit: Also a lazy o2 sensor can cause a slight missfire at idle (lean missfire), idle to fluctuate at idle (sometimes caused by intake manifold leak) flames from exhaust (o2 sensor makes ECU make engine run rich longer than it should).

[caliber676]

Sounds like a coil pack

[Bruizer]

plugs

[kyledude351]

Did the 'unplug 1 by 1' check while running, cylinder 4 coil pack totally dead
going to swap them all with the coil packs off my other rb26

[Godzilla32]

good man good happy u figured it out rb26 can be a pain in the anus if ya dont know ur way around one, you will eventually