P0300 Error, then P0301

[coleman]

Briefly, my 02 TB with just over 150K starting idling a little rough when the engine was under load. Then about a week later, it threw a P0300. I checked it a few times and it kept giving the same error, then one time it finally gave me a P0301. I changed the coil pack for the #1 cylinder and the engine ran fine again - except for the rough idle under load.

Could another coil pack be starting to go bad? Why would one bad coil pack cause the computer to sense multiple cylinder misfires?

Thanks, guys.

 

[rywegh]

I believe the reason you got the P0300 was the computer sensed the misfire but that it hadn't occured enough times for the computer to know which plug was bad. Once the error hit enough times the computer then gave you the P0301 error.

If it is starting to run rough now and you are at 150000. When was the plugs last changed? Delco 41-103? Did you clean Throttle body while replacing the coil pack? What about fuel filter?

I just went through this headache 3 months ago. You can almost eat off my throttle body it was cleaned so much.

 

[coleman]

I believe the reason you got the P0300 was the computer sensed the misfire but that it hadn't occured enough times for the computer to know which plug was bad. Once the error hit enough times the computer then gave you the P0301 error.

If it is starting to run rough now and you are at 150000. When was the plugs last changed? Delco 41-103? Did you clean Throttle body while replacing the coil pack? What about fuel filter?

I just went through this headache 3 months ago. You can almost eat off my throttle body it was cleaned so much.

Thanks for the info on the errors. It's probably time to keep the code reader and some tools in the trunk all the time. Thankfully, I wasn't far from home when the engine started missing.

Plugs and fuel filter replaced at 135K. Throttle body cleaned at the same time. When I had put the coil pack in, I checked the throttle body and it was still squeaky clean.

I think I'll get a bottle of Techron tomorrow and dump that in the tank. It certainly couldn't hurt.