So, I live in NY and the recent hurricane brought with it a serious gas shortage problem. I used some old fuel in the garage to make up for the shortage and within a day, the car was starting hard. I fueled up the following day with fresh gas, but after the hard starting, there was a loud tick that sounded like it was on top near the valves.
The tick went away on its own the next day, and the car started starting normally again. I threw 2 codes. Random multiple misfire during the hard starting, and then p0303 cylinder 3 misfire that I can not clear.
I added seafoam to the fuel and marvel mystery oil to the crankcase, (I know, some people dont like additives). It seems like its running ok on the highway with full power, but idle is very rough still. I changed the #3 injector, checked the coil, and changed the plugs, (they were do anyway).
I still have a miss in #3, and those two plugs were oily and dark. Obviously there is a firing issue, but I think the spark is ok. Can this be a valve issue. I know there were some valve issues with the Hemi, but the car starts and runs ok, except for the missfire. Im not even sure this was caused by the fuel, maybe its coincidence...
If the valve was sticking or the seat was fallen, would that cause the misfire issue and allow the car to keep running well for the most part?
The car is not ticking anymore and sounds normal except for the misfire.
What should I check/fix next?...