So, back in the eighties, a contractor I knew bought a truck from the auction. He did a lot of driving in remote areas, loved his newer model truck, took good care of it, and it never gave him any problems. He had a small crew; guys came and went, but at a certain point, he ran into financial difficulties and had to lay a couple guys off. He had trouble making payroll. Eventually, he got back on track and his business expanded.
Getting back to the truck... around the time he had to lay people off, the truck started having problems. Specifically, it would die unexpectedly, like it was out of gas. Then, mysteriously, after a few hours or a couple of days, it would start up again. Buddy just couldn't figure out what was wrong; the goddamned thing would choke out in the middle of nowhere. He would have it towed, and when it was taken off the hook at the mechanic's shop, it usually started right up. They replaced the fuel filter, the fuel pump, checked the lines, checked everything. Finally, it reached a tipping point.
Buddy was out in the country, cheating on his wife with some bimbo, and the goddamned thing died again. Keep in mind, sometimes the truck would run for a couple months without a problem. Now, he's stuck out in the bush a hundred miles from home with some bimbo and he had to be back in town for Easter to go to church with his wife and kids. This was in the days before cell service was widely available; cell phones were expensive, poorly serviced, and mostly, they were just a status symbol. When the booze ran out, he and his floozie had to walk two hours on the fireguard before someone came along and drove them into a town. That was it; his wife was going to bitch at him for missing Easter church service, and she already kind of knew he was cheating... but that's a different story...
Now he was supremely fucking pissed off. He could easily have sold the truck to some other sucker or just left it in Winnipeg and taken one of his other vehicles, but he just HAD to know what the hell was going on. Again, he had the truck towed, it comes off the tow truck, and it starts right up. What the fuuuck? This time, after having some drinks, he told his mechanic to strip the goddamned thing down and find the problem, no matter what the cost; he HAD to know. Incidentally, a former employee of his that was on good terms with him used to love teasing him about the truck. Always, a big smirk on his face as he asked, "How's the truck running, Marc?" So, finally, he pissed away a whole lot of cash as the mechanic methodically replaced the entire fuel system.
"Fuck it, replace the goddamned gas tank." Finally, everything was replaced and the truck never gave him any problems, but after several months with no problems, he still had to know. And then, he remembered one last piece of the puzzle... the gas tank. He called his mechanic. Yeah, he still had the old gas tank. One last thing he needed to see. They cut open the old gas tank and... there it was. The thought of the leering face of his former employee, "How's the truck Marc?" Inside, they found and old rag. "That cocksucker!" All this time he couldn't prove his guy was the one who did it, but someone had methodically pushed a cloth rag down into the gas tank. That fucking rag would float around, and every so often, it would cover the fuel intake and the motor was starved out of fuel. Then, when the truck was lifted to be towed, the rag would release and float around for a while and do it all over again. Rag in the gas tank!