I have a 91 2.3 5-spd and recently it has developed a problem. I hold the accelerator on the floor, and the engine revs to about 2000 rpm, then drops of and then revs back up, without letting off the pedal. It does it in all gears, and the surge seems to be about a three second cycle. Any help will be appreciated.

could the catyletic converter or exhaust be clogged that would be my first guess. Could also be low fuel pressure of clogged fuel filter