04 G35 coupe.

I got the engine light last week. I checked it out and got the fault code P0300. I looked up the P0300 code on the forums and found out that it was random misfiring. I found some other threads with similar issuses. But my issue seemed to start off when i put gas at the 76 gas station. It was my first time using gas at 76 gas staions.

I put 91 octane like i always do. I filled my tank and as soon as i started my car it felt and sounded different. I car idled rough, it shook while I was still in park. I drove off and the exhaust sounded different than normal. I also noticed less power. My car was running fine beforehand.

My engine light comes on and off randomly. And sometimes it blinks. From what i've been reading is spark plugs might be bad, coils, or vaccum leaks. I dont know much about car mechanics, but i'm thinking it had to do with the gas I put. But it doesnt really make sense why some gas would cause my misfiring. I drove my car to 1/4 tank of gas and filled it up with Chevron 91 and hoped it would fix the problem, it didnt.

Anyone have any ideas? Should I take it to the dealer, another mechanic, or should I just ride it to empty and fill it? Thanks for the help.

 

It could be any number of things... Check the battery first, sometimes a bad battery can cause those problems. If the battery is good, I would try to clean the fuel injectors and check your spark plugs and coils. Check the vacuum lines for cracks. If you still don't know what it is, I would bring it to a mechanic. If it's not that, it could be anything; EGR valve, fuel pump/filter, bad fuel injectors, etc, etc..

From what you've described, I highly doubt it has anything to do with the fuel..

 

Thanks, i'm going to take it in and hope for the best.