Darrell,
Sounds a lot like the AFM is acting up. Look up the article in the archives
about the air flow meter. It happened to me on a 45 day trip across the US,
but this article saved the day. I replaced the AFM and added the VW AFM
harness "fix," three years later and still running great. It may be your
problem.  I can't be certain, but it may be worth considering.
Robert