Volkswagen Repair: VW vanagon loss of power, vw vanagon, aircleaner

Question
I recently had my '89 wolfberg vanagon serviced with a new carburetor and tune up in order to pass smog but now the car is having problems on the freeway and at stops.  Unfortunately the shop I took it to is in my hometown a few hundred miles away and I don't want to drive it back there because I don't think it'll make it.  Anyhow the problem is this.  When I'm on the freeway I can get the car up to about 65-70 for a short while and then I feel the power just let up causing me to top out at 50.  Also when I'm at a stop the car will idle so low that it dies unless I put it in neutral and keep the rpm's around 1,000.  I could really use your help in trying to solve this dilemma.  Thanks a lot.  

Answer
sounds like it is starving for fuel.  Check if there is an inline fuel filter and change it. If problem still there then when it does that again,. shut off the car immediately, take off the aircleaner and the top of the carburator and look into the float bowl to see the amount of fuel.  If it is way at the bottom then the float needs adjusting.  Just bend the tang that stops against the needle in such a way that the fuel bowl has to be fuller for the needle to be fully pressed in.Its either those two things or you have a fuel pump problem