Misfire, erratic idle, occasional stall

PAPPEEM

MEMBER
1999 CHEVROLET LUMINA
6 CYL
FWD
AUTOMATIC
96,000 MILES

Following a flow chart, my scanner told me#6 had mis fires. Wires and plugs are good. Moved coils, still showed #6 misfire. Replaced ignition module. Now shows#1-5-6 misfire. Is there something I am missing, other than my mind? Prior to this, I had fuel filter &fuel inj flush for same problem

Engine 3.1L.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

More than likely if you swapped the coil and have misfires on all cylinders on that bank that the replacement coil is faulty.

So, let's go back to the last coil and get the cylinder 6 misfire back.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Then we need to find out how you know the plugs and wires are okay.

I would suggest we swap the components on this cylinder to another on the other bank and see if one of them causes the misfire to move.

This means the injector, plug, wire. Then we need to do a compression check on this cylinder and a couple others just to get a baseline.

https://www.2carpros.com/articles/how-to-test-engine-compression

I am attaching the spec below, but you should have about 120 PSI and if you have less than 100 PSI then that is an issue.

Please run through this info and let's go from there. Thanks

Image (Click to make bigger)