Bad spark plugs or an ignition coil can cause ignition misfire, which will illuminate the Check Engine Light.
Average mileage: 133,168 (52,000–189,769)
Engine affected: 4.3L V6
22 people reported this problem
Had a stalling problem, that went away, now it chugs and has a misfire, plus gas caused the stalling when I went back to regular it didn't stall, P0304 cylinder 4 misfire.
one morning the check engine light went on and the car rode rough. I figured bad gas or fuel filter. 2 miles on the check engine light started blinking. Call to mechanic told me to get the car to him ASAP. Drove 6 miles home going 10mph on the shoulder, praying all the way. Bad ignition coil. He replaced all the plugs. Got off cheap, could have been catalytic converter or worse. Otherwise great highway car.
Misfiring plugs or coils. Advance Auto put a tester on it and said 2 of my coils were misfiring. I am in the process of changing the plugs and all the coils. I found 8 coils online for 125.00 new. The car has 256,000 mi on it