I did a bad bad thing... Sadly, I knew I was doing a bad thing when I did it, but did it anyway. I was dropping the fuel tank on another car that had been sitting for maybe 2-3 years. I drained the tank (about 5 gallons). Not knowing what to do with the gas, I figured, I'd burn it off in the P5. I realized the gas was probably flaky, so I cut it with fresh gas (the bad gas appeared clear, there wasn't any rust, or any other contaminants). I put in 2 gallons of the bad gas, with 5 gallons of fresh gas, and there was probably an additional 3 gallons already in there. I drove the car without any incident whatsoever, until it was down to about 3 gallons. I then figured what the heck, the gas seems okay, so I dumped in the remaining 3 gallons. The car drove fine initially, but then got worse, and intermittently seemed to go into a "low power" mode. The car ran rougher, idled lower, and just generally had no power. I call it a "mode", because it seemed to just transition between being fine to running rough and then back. There was very little in between. Some times it would go into the mode, if you shut off the car, waited a minute and restarted it'd be fine, other times it wouldn't. Sometimes it'd just switch back and forth.
I put in another 5 gallons of fresh gas today, so for those keeping score at home, 15 gallons of fresh gas to 5 gallons of questionable stuff. It initially drove in rough mode, but within a few minutes switched back to normal mode, and seems fine. After it switched to normal mode, I've been running it in low gear/high rpm to try to give it an Italian tuneup. When it first went into rough mode, it threw a P0300 (misfire on all cylinders) -- and continues to do so whenever it goes into rough mode. I've also seen it throw a P0421 (inefficient catalyst warmup) after the P0300 came on. I hope I haven't damaged the cat, I haven't heard any backfires or loud/abnormal noises.
I'm wondering what the deal with this modal behavior is. I didn't expect anything like that. Only thing I thought was maybe the plugs are fouled or something. I'm also wondering why its continuing to do that. I doubt that the concentration is more than 20% of the questionable gas, and it was probably at 25% on the first round where it drove fine. I assume if I run it down to 2 gallons again, add 5 gallons it'll be down to about 7%, and if I do that one more time it'll be down to 2%, and at that point its hard to imagine that it's doing anything. I've heard most gas cars can run fine with up to 10% diesel in them.
Thoughts? Other than I'm an idiot?
I put in another 5 gallons of fresh gas today, so for those keeping score at home, 15 gallons of fresh gas to 5 gallons of questionable stuff. It initially drove in rough mode, but within a few minutes switched back to normal mode, and seems fine. After it switched to normal mode, I've been running it in low gear/high rpm to try to give it an Italian tuneup. When it first went into rough mode, it threw a P0300 (misfire on all cylinders) -- and continues to do so whenever it goes into rough mode. I've also seen it throw a P0421 (inefficient catalyst warmup) after the P0300 came on. I hope I haven't damaged the cat, I haven't heard any backfires or loud/abnormal noises.
I'm wondering what the deal with this modal behavior is. I didn't expect anything like that. Only thing I thought was maybe the plugs are fouled or something. I'm also wondering why its continuing to do that. I doubt that the concentration is more than 20% of the questionable gas, and it was probably at 25% on the first round where it drove fine. I assume if I run it down to 2 gallons again, add 5 gallons it'll be down to about 7%, and if I do that one more time it'll be down to 2%, and at that point its hard to imagine that it's doing anything. I've heard most gas cars can run fine with up to 10% diesel in them.
Thoughts? Other than I'm an idiot?