Bonniville SSEI Missing Problem!

HEISE123

MEMBER
1992 PONTIAC BONNEVILLE
6 CYL
FWD
AUTOMATIC
140,000 MILES

1992 Pontiac Bonniville SSEI runs but has a miss to it. Checked all plugs and wires and they are good. Used a spark tester as well and there is juice from coils to all 6 plugs great spark. When she hits overdrive is shutters pretty good as well

Changed plugs, wires, ignition coils, and modual, MAP sensor, MAF sensor, changed Injectors everything! I put a spark tester in between the plug and the wire and good spark all around still says number 5 cly! When u drive it its great all the way up until overdrive, once in it shakes real good till about 65 then u can barly notice it I am soconfuse! I am very knowledgeable with all GM cars and trucks and this is honestly a first!

pleasehelp!

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

We need to do a couple more things. First and foremost is check the fuel pressure when this is happening.

Many times the fuel is overlooked as a cause of this so here is a guide that will help with the pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Next thing is to check the compression as if you have low compression, it will cause misfires at higher load situations until it gets worse and causes larger issues.

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

Once we know what these things are then we will have a better idea on what the possible causes are.

Let us know what you find with this, and we can go from there. Thanks