I have a 2004 Jetta GLS TDI. I have been having a low power (limp mode?) issue for some time. It won't tach up past 3000 and sort of (not sure how to describe it) misses when it has to work hard such as going up hills or when I am accelerating. I had the fuel filter changed and ever since when I turn the key on I hear what sounds like the whine of an electric motor that seems to be coming from the engine compartment. You hear when driving also. My mechanic changed the fuel pump, the one located under the back seat, but that didn't solve the problem. He took it back out and put the old one in but the parts company would take it back so now I have a spare fuel pump to the tune of $340 My mechanic mentioned that my Jetta has two fuel pumps and I am wondering if the other one might be bad?