Hmmm.. well, I'm new to the whole VX thing, and I've got to say that you all are the nicest group of people! Anyway, I bought a 99 VX last month and had to tow it home because it was running really bad.
Here's what happens when I start it up:

Runs ok for first 15-20 seconds, then starts to idle rough. If I give it any gas it revs slowly then wants to idle very low. Almost no power at all when I put it in gear and try to drive it. It "pops and coughs" when the gas pedal is depressed.... Also, there is a strong hissing noise coming from the throttle body area, which leads me to believe that it might be the IAC motor... even though I did pull it out and looked to be funtional when turning the key in the on/off positions multiple times. Could it be the MAF? MAP? O2 sensors? Plugged CAT? Timing? I'd love to see if anyone else has had this problem. Thanks a ton in advace!