surging

i jus got a tune up and i put a new distributer cap on my electric distributer and my car still surges aftter i floor it or when im goin past 70mph..what else can it be.....

help me!!

With out being there to actually feel what it's doing it's a little hard to tell. Is this a condition that you have always had or is it something that just started? Normally surging is caused by a lack fuel, some of the basics to check:

Did they put a fuel filter in it?

What is the condition of the fuel line from the tank to the fuel pump? (A leak here can cause a fuel starvation problem.)

What is the condition/age of the fuel pump?

Is the car supposed to have a vented fuel cap, and if not is the tank vent line clear?

And finally if it is determined that it is a fuel starvation problem and everything else checks out, you'll need to pull the sending unit from the fuel tank and check the condition of the screen on the end of the fuel pickup.