Derek1

I have a 2002 Audi A6 C5 2.5 TDI. The car when cold starts normally, when I drive it, I don't seem to feel any loss of power or anything strange, but after 20-30 minutes of driving car starts stalling and then it won't start until it gets a bit colder. Am I right to think that it's the fuel pump that's at fault and when it gets hot, it stops supplying enough fuel? If so, which one would it be? The one that's located in the tank, or the one that's under the hood? What else could it be?

My coolant temp sensor was bad. First it was gradually going from 60 to 110+, after that it was constantly at 90. After I replaced it the temperature gauge is showing normal coolant temperatures, but I'm pretty certain that my car started stalling when hot only after this replacement. Can this somehow be related?