Pontiac Grand Am...

[ghettoandgangsta]

...Issue?? I have a 1999 Pontiac Grand AM SE.
The other night i was on my way home the service engine light and the trac off light started coming on

I took it to the automotive store to have it checked it says cylinder 4 misfire.

Changed the spark plugs and its still doing it.

You can hear a noise coming from the exhause pipe and the car jerks unless i pick up speed

What is this??

 

[cd5tuner]

I need help with this too... please anyone???

 

[wde3477]

Do you have the specific trouble code?

May also be a plug wiring problem.

 

[Goatman]

Chances are it is a injector plugged and has nothing to do with the plugs or wires .. it is a really common issue with FI cars it will registor a misfire but the system won't tell you (or can't) tell you weather the injector is not fireing or it's an ignition miss
Either will registor as a missfire on a single cylinder..
you can try a can of injector cleaner but most aren't strong enough to clear the clog you may have to either take it to a dealer or shop and have an induction clean (pressurized cleaning) of the system done
if that dosen't work injector replacment may be in order..

The other thing that comes to mind is if the car has the Quad style engine with the engine cover that has the coil pack built into it it may have "carbon tracking" on the posts or a bad coil assembly causing the missfire I would need to know the engine type to be of more help but that should give you a starting point..

The other thing that sticks in my mind is the "trac" light came on which sometimes is indicative of the alternater going bad which also can create a misfire situation when the power level drops in the battery the ignition system will start dropping cylinders randomly.. but im assuming that is not the case as you diden't mention any other issues with the car not starting ... but it may help someone else..