[Vwdiesel] fuel starved

[cosborn at epix.net]

'81 1.6L pickup

I live in a mountainous area and I often have to downshift into third gear to maintain speed while cresting a hill.

When I have the pedal to the floor at high rpms lately, the engine will hesitate and loose power like the engine is starved for fuel.  If I back off the accelerator pedal a bit, the engine goes back to smooth operation, but of course I end up going quite a bit slower.

It does have a brand new fuel filter on it, and it just had a recent head gasket replacement.  The timing appears correct as it doesn't smoke and does have adequate power and gets 50mpg, but I have not actually had the pump timing checked with a gauge.

Any suggestions? 

Craig O