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OnlineHelp, Mechanic
Category: Car
Satisfied Customers: 3423
Experience:  Mechanic
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Trac off light comes on, Service Engine soon comes on and car

Customer Question

Trac off light comes on, Service Engine soon comes on and car shakes...took it in, was told cylinder 1 is misfiring, told to have ignition coil and spark plugs replaced. Did that, and the car is shaking again as well as lights coming on again, the very same day these parts were changed. Any suggestions on what it could be?
Submitted: 8 years ago.
Category: Car
Expert:  OnlineHelp replied 8 years ago.
Hello and thank you for choosing Just Answer.

Year, make and model?
Customer: replied 8 years ago.
99 pontiac grand am 4 cylinder
Expert:  OnlineHelp replied 8 years ago.
Is the code they got P0301 (Mis-fire cylinder 1)
Customer: replied 8 years ago.
Yes, and they said to replace the ignition coil and spark plugs. They did, drove the car home , trac off light came on again, service engine came on again, and the motor is shaking again.
Expert:  OnlineHelp replied 8 years ago.
Thank you.

They need to check the fuell injector to make sure it had pulse and check the injector flow for #1.
You can switch injector #1 with another injector and see if the code changes. For example the current code is P0301 (cylinder #1) exhange injectors with cylinder 3 and see if the code becomes P0303 (cylinder #3) which would indicate a bad injector.

Also have them run a compression test on cylinder 1.