944 turbo throttle dropout problem

1986 944 turbo, 165,000 miles, standard transmission; Throttle drops out sometimes only during driving conditions. When I am driving, the throttle will cut out completely, wont restore untill I put the accelerator back to idle position, then throttle returns to normal, sometimes recurring again after I accelerate again. This happens alot. Engine idles fine, and has never cut out at idle. Car was stored outside for many years. Any ideas would be helpful.