Thanks Chris, not quite sure if I need one yet...having a hell of a time diagnosing what's wrong. Today it drove somewhat fine on the way to work and then at lunch break I took it out for a drive to see if it would act up. On the drive I had a newer GTI riding my ass, then at next light he pulls in to merge lane on the right. I was trying to decide whether to let him by or go for it--knowing engine would crap out. Light changes and he takes off fast, instinct kicks in and I floor it...well for fucks sake, car takes the hit hard, hitting 11-12 lbs boost and goes flying by him in an instant and pulls hard until I let off around 80....hasn't run this well in a while. So I think wtf and take it down some quiet roads by my work and run the crap out of it. Runs great! No surging, even idle, no misfires...cured! Get back to work, all's good, shut her down then decide to start up for last check...vacuum and idle drops, misfires on all cylinders, starts surging so I tap the gas and it clears up and idles smooth?!! Wouldn't a dying pump crap out all the time?
Anyone out there have experience with a bad pump that had similar symptoms?