Problems starting VW Passat - help diagnosing?

Hey everybody. I figure after listening to Car Talk so long for entertainment, I should maybe try to get some help on my own car problems. =)

I have a 2001 VW Passat GLS V6. Generally runs pretty well, but I have some issues starting the car. If the car has been sitting longer than a couple hours (i.e. a day or more), it has a little trouble starting. I have to turn the ignition several times (usually 3 or 4) while pumping the gas pedal to get it going. On the first couple tries, the engine doesn’t “catch” (for lack of a better term) - you can hear the car trying to crank but the engine just doesn’t turn over.

Even after it catches, I have to rev the engine several times or else it will shut off again. As I’m doing this, I hear several “pops” or “knock” sounds, and with each of those sounds the engine feels more engaged… and finally once all the sounds are gone, the engine is fully engaged and the car drives fine after that.

It’s also possible that the problem is worse when the car is parked on a hill (sloping upward, i.e. the front is higher than the back) but I can’t really be sure.

I don’t believe the problem is battery-related, as the radio, AC, windows etc all work with no problems even as the engine is having this issue.

I briefly discussed this with a mechanic friend of mine and he said he thought the problem might be related to the throttle body.

My questions for y’all -

  • Is there more I can do to diagnose this problem myself? Maybe some easy ways of investigating the throttle body without chopping my hand off? The most in-depth work I’ve done on the car is to replace the spark plugs by myself.

  • If it turns out I need to replace a part like the throttle body, is there a good source of used VW parts online? I’m not in great shape financially right now, so I’m trying to avoid more than a couple hundred dollars on repairing this if at all possible.

Anyway, really appreciate any advice you’d have.
Thanks!
Chet