Mazda 929 Engine Problem

1989 Mazda 929, 18V SOHC engine. 123K, well maintained (but not used a lot lately). Took the car out for a ride today. Stopped at a store, when I came out car was a little difficult to start but fired up. Right away I felt a severe lack of power and engine would not rev up past about 3K. Drove to a gas station to fill up since the car really did sit for about 2 months and fuel was a bit low. Filled up, car wouldn't start. Crank and sputter. Called for a tow. While waiting, I did get it going again but severe lack of power, I was able to move the car but just barely. Check of trans fluid did not show any loss or burnt fluid. Oil in engine was fine too. With engine idling, quickly pressing acc to the floor doesn't do much, it will eventually rev up but runs very very rough. Feathering it will let engine rev but not cleanly. Could a timing belt jump cause this type of sudden problem? Weak fuel pump? I thought of a bad igniter but think if it was bad I'd never get it running. I'm leary of the timing belt since the place that did the job didn't do a very good job, lots of evidence of sloppy workmanship. Guidance sought and greatly appreciated.

Thanks.