My in-laws car had a P0300 code come up (random misfire detected). Where do I start? Could it be the plugs, coil pack or oil leak going into the plugs?
That's the only code that showed up on my scanner. The car has new timing belt, water pump and serpentine belt. These were replaced early this year. I don't think there is any vibration, but will check and see what exactly is going on. I think it may be the valve coer gasket leaking oil and going into the plugs.
Just an update, the check engine light randomly comes on and goes off now. I didn't do anything, recently filled up some gas and then the light went off and so far it is staying like that....weird!
How many miles? when were spark plugs last changed? (or were they ever changed?)
it's very possible that one of the ignition coil packs/modules is the cause here
The car has about 135K and the plugs were changed early last year. I'm think it could be the coil pack or the plug wires, because once I started it the other the day, the car had a slight shake and when I accelerate it, the car would run fine and then it was okay. So far it is running fine, but will keep an eye.
Whenever I get this code, its because there is water in the sparkplug hole between the boot and the plug. It grounds out to the head giving you a random misfire. Sometimes I hose off the engine and forget to blow the water out of these areas.
Just an update! After few months without any problem (didn't replace anything), the check engine light came on two weeks ago , scanned it and it showed cylinder 6 misfire (don't remember the code). Turned the check engine light off and drove it for another week without any problems, then the check engine light came on again yesterday after driving it for few minutes. This time the check engine light flashed for few seconds and the car slowed down, would not accelerate enough, could only drive it like 20 miles an hour and brought it back home. Could it be that the ignition coil pack is bad?
I was just looking online for the ignition coil and I see some brands selling two kinds (same side), one with a white connector end and one with a black connector end. Does anyone what the difference are for these coils? I know that the prices are different!!!
Thanks, I also got a great deal on the coil. I ordered it online from Advance auto parts and used coupon code, then picked it up from the store. The one I got was the BWD brand, and it is made by Bosch. It looks exactly like the orginal one in the car.
I replaced the passenger side coil with new plugs a month ago because it was running rough with the random misfire (same code P0300) and it ran well until yesterday it started to do the same thing. I scanned this evening and it showed the same code P0300. Also, one of the O2 sensor has been bad for a while and has the code for that. Could that be the problem for the misfire or could it be something else?
No it would not cause a mis it self but if its faulty it could cause the ECM to either run lean (not enough fuel) or rich ( to much fuel) which would cause a mis. I would just change bank 2 coil and o2 sensor and add seafoam and go from there
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Cadillac Owners Forum
4.8M posts
369.7K members
Since 2002
Cadillac Forums is the perfect place to go to talk about your favorite Caddys including the ATS, CTS, SRX, Escalade, LYRIQ, Vistiq, concept and future Cadillac models.