It could be the timing. Question is, has it been like this since the second you had the work done, or did it happen later. If it happened later, chances are that it jumped time. You can attempt to adjust the timing first, following the below procedure. If that doesn't work, you will have to remove and reset or replace the belt. Some techs do not correctly tighten the timing belt tensioner, so you may want to look into that, if you are able to get it back into time. I also attached some images for aid.
1. Remove the rubber cap from the inspection window of the cylinder block.
2. Start the engine and allow it to warm up (cooling fan comes on).
3. Connect the ORN/RED and GRN/WHT terminals of the service connector (BLU) with a jumper wire.
4. Connect a timing light to the No. 1 ignition wire; while the engine idles, point the light toward the pointer on the flywheel (for M/T), or on the drive plate (for A/T).
5. Adjust ignition timing to: 15 +/- 2 BTDC @ 700 +/- 50 RPM
6. Adjust as necessary by loosening the distributor adjusting bolts, and turn the distributor housing counterclockwise to advance the timing or clockwise to retard timing.
7. Tighten the adjusting bolts and recheck the timing.
8. Remove the jumper from the service connector and replace the rubber cap to the inspection window.
Images (Click to enlarge)
Thursday, January 26th, 2012 AT 10:58 AM