I used to own an almost perfect Volkswagen Passat TDI wagon. I say almost perfect because it suffered from some unknown demon that kept acceleration leisurely and forced it into limp mode when approaching highway speeds. The previous owner had brought it to his local Volkswagen dealership, and he decided to sell when the dealership mechanics couldn’t figure it out.
The seller convinced himself the problem was poor flow from the fuel tank and he tried an eBay-sourced inline fuel pump to fix it, but that diagnosis proved incorrect. I bought the car for $600 and drove it home slowly. All I had to do was figure out why it had a 0-60 time of 43 seconds and a top speed of 65 miles per hour.
In the end, with the help of Jalopnik readers dieseldub and bhtooefr I found the real issue was a leaky boost pipe on the inlet side of the intercooler. It looked OK, but it would split open under boost. Somehow the dealership missed that. I had a friend with a pile of these hoses in his garage, so it would have been free for me to fix.
But as COVID hit hard and my anxiety shot off the charts, I was too stressed out to undertake even a no-cost repair. I sold the car. The buyer later informed me that my diagnosis was on point. He fixed the hose and the car drives great now. I regret the decision to sell almost every day.
So how about you? Have you ever left a mechanic baffled by your particular set of automotive woes? Have you ever had to throw in the towel and admit that your car was possessed by a demon you couldn’t exorcise? Have you ever had something go wrong that even a trained mechanic couldn’t fix?