I didn't give up. Decided to pull the plugs even though they were new as of 3 weeks ago. What with all the misses and stuff, I thought maybe they were a bit fouled. Holy sh*t the entire bank 2 were completely sooted out, like they had been running real rich. Bank 1 was fine. I replaced the plugs and test drove it. It did the same thing, started running terrible and the SES light started flashing, same code thrown P0300 but I got it home quick. Which got me to looking at what might have caused just one bank to foul. Then I remembered way back, right after I had fixed the heater hose that had come off and the engine had overheated, there was a DTC P0174 bank 2 upstream O2 sensor lean or voltage out of range. That could have been an intake leak which is what I thought it was. It could also mean the O2 sensor was bad. And from reading up on a bad O2 sensor, I learned that if the PCM is not getting readable data from an upstream one, it will run that bank rich as opposed to lean since running it rich won't cause engine damage but too lean will. It will foul plugs and cause misfires because it's so rich obviously, and throw codes, but it won't melt pistons. Which is real good in the case of a FI engine especially. I did keep an eye on the AFR on bank 1 with my AEM wideband but bank 2 I couldn't see. So I threw a new bank 2 upstream O2 sensor in and I'm almost positive I have it fixed. I just did over an hour of all kinds of driving and it's running perfect. Both the other times I took it out today it only made it a few blocks before it started running like crap and throwing codes. Fingers crossed!
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