I have a 1997 tracer/same as escort... When I step into the gas while car is in park there is a delay in acceleration... It dosent seem to effect the car while driving down the road, but im worried that the delay might "rob gas mileage" could it be caused by exhaust restriction or air filter... Or do all these cars have a slight stumble...is it Normal..?

not normal... could be a number of things.
I would expect that if it did it in park that it would do it when driving too though...
CHeck plugs/wires, vacuum, things of that sort.

Exhaust restriction and/or air filter could cause this. Replace the air filter if it's never been done. You can check for exhaust restriction by hooking a vacuum gauge to a port off of the intake manifold. A reading less than 16 indicates a plugged up Catalytic Converter or muffler.

ummm could be your transmission slipping mine does that but i have lived to deal