Check engine light turned on for code P0303?

2018 JEEP GRAND CHEROKEE

86,000 MILES • 3.6L • 6 CYL • 4WD • AUTOMATIC

MATT FRASER

MEMBER
1 POST
FOLLOW

I got a check engine light code for P0303. Brought it to mechanic and he said it could be spark plugs or ignition coils. So, to be safe I replaced all of the spark plugs and ignition coils. Fast forward a week later I get the same code again. Not sure what to do now. Maybe could be a sensor on the intake?

Oct 11, 2023 at 5:00 AM

STRAILER

CERTIFIED EXPERT
53,854 POSTS

It could be the fuel injector has gone out, but we should remove the spark plug on #3 to see what it looks like, if it has very little color on it the fuel injector could be bad. Here is a guide on misfires that can be helpful, and I have included how to change the fuel injector out.

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

These engines had problems with the valve train, when the engine is running can you hear ticking coming from the #3 cylinder? Check out the images (below). Please let us know what you find.

Images (Click to enlarge)

Oct 11, 2023 at 8:21 AM