2000 Pontiac Grand Am Misfire!

[Dewitt88]

Ok I have a issue. Its really confusing me.

Cylinder 3 Misfire

I changed everything. ICM, Dist (Thing), Plugs, Boots, Injectors, Regulator, Fuel Filter, I can keep going


Heres what is wierd. If I pull the #3 Injector wiring off the car runs like a misfire.

The car runs and drives like normal. Its not sluggish or anything. I am a mechanic and I can tell when its a misfire but this car is not acting like its misfiring at all. Although the OBD II scanner says it is. I have a SES light. I also have a bad cat converter, would this cause the car to act like this??

2000 Pontiac Grand Am SE1, 2.4L 4 Cylinder Automatic


Any help or ideas would be great. I am totally lost. I had another mechanic drive it aswell and he said there is no misfire so why am I getting the code???

[xeroinfinity]

Did you inspect the injector wire harness ??
They can get broken and cause all sorts of misfires.

You injector could also be clogged or bad.

Check the ohms resistance acrossed the injectors.
Should be - 1.95-2.3 ohms with EGR,
and 11.4-12.6 ohms without an EGR.
If any read realy low I'd say its a bad injectors.

[Dewitt88]

But all the injectors are working? Would this matter?

[xeroinfinity]

Well if you have a misfire and you jsut replaced the ignition system components then it has to be something fuel related. So yes it would matter how well the injectors are working. If the readings are off then that would indicate a problem.

Intermitant misfires are very common wit these newr GA's.
At some point my SE has had everything replaced, most twice. My problem was the wire harness for the injectors and a bad ground on the intake.

Hope that helps.

[Paultl80]

I had a similar issue with my 2002. The 1st and 4th weren't firing right.
I replaced the coil pack. -Not fixed.
I replaced the ignition control module. (that small pack screwed into the Coil Pack) -Fixed.

Note: The ignition control module is the size of a deck of cards and cost about $100.

[xeroinfinity]

Welcome to AF Paultl80, and thanks for the tip!!

But please look at the post dates before bringing up old threads, anything over 3 months is old.

this is closed!