Yeah, things happen. I got a call last night from a friend who had borrowed my truck. We are good friends.
However, he said that after a fillup, the truck started to run like it had "bad gas." While talking on the phone with me, it dawned on me that he might have put perhaps half a tank of gas in the truck during a mixup at the pump. Later, he realized he put a full tank of gas in, not half, because he checked his two receipts and both said gasoline. I am not sure how he made it 15 or 20 miles on what amounts to 3/4 to 7/8 gas. Maybe the electronics nowadays are good at adjusting the timing of the injection due to, ahem, "bad gas." Good thing he wasn't pulling a load at the time.
Well, me and some other guys went to help get the fuel drained. The truck was on the side of the road parked on a flat grassy strip, thankfully. I'm not sure if a gravity drain was possible or not, but we ended up disconnecting the fuel return line near the first fuel filter, under the driver's side, and put a hose from there to some gas cans.
It took awhile doing it this way, which is why I wonder if there is a smarter way to do it. We just turned the ignition on and back off a few hundred times to pump the gas out into the cans. Once the tank was empty (hours later), we put about a half gallon of good diesel in and drained the tank once more (a little flush). I then added about 5 gallons of diesel plus a rich Cetane booster to the tank.
Since I figured that the fuel filters may not be in great shape after all of this, I went ahead and opened up the one in the engine compartment... but it was almost dry inside there, so I just sopped up a little diesel/gas and put it back in. For the bottom filter, I just drained the water plug and I didn't have the 36mm tool to remove the filter, so I just left it.
When we primed the fuel again and turned the engine over (by now we were being jumped due to a low battery), the engine fired up immediately. Someone was watching the tail pipe and said that it started on black smoke but cleared up pretty quick. I was at the front and noticed a normal sounding start, but a bit of a thud/thud/thud noise I wasn't used to hearing... It lasted from perhaps 15 seconds to 60 seconds after starting the engine.
I drove it home and it didn't seem to have any problems. If anything, the gray bottle of PS cetane booster probably gave the engine a bit better performance.
So... anything I should look or listen for? You think I need to take it to a dealer?
Side note: my friend drives diesel trucks all the time... he knows better. It was a fluke.