Your engine sounds pretty much like mine did when I changed the timing belt. I don't know if your problem is similar. However, in my situation, the problem was the distributor rotor wasn't lined up at #1 plug with camshaft lined up at TDC. Also, make sure you check that your plug wires are in the order 1,3,4,2 (clockwise on distributor, #1 is closest to engine block, #1 cylinder is closest to timing belt cover).
To check your distributor, pull off the top timing belt cover, take a socket wrench with I think a 16mm? socket and manually turn the camshaft sprocket until "OT" is lined up with the arrow on the inner timing belt cover. Then pull the distributor cap and make sure the rotor is pointing at the engine and the long edge is parallel with the sensor plug at the base of the distributor. If it is not, then you will have to remove the lower timing belt cover and either replace the belt/tensioner or readjust (IMO I'd just replace...since I'm in there already). An excellent write up of this procedure can be found at:
MKIII Timing Belt and full water pump page.
Also, double check your spark, pull the plugs and test them one at a time. If you have little or no spark on any/all plugs, pull the ignition coil (located on firewall...just follow the ignition plug from the distributor) and check for cracks.
Finally, does your check engine light flash (or is steady) when the engine is on? If you have an OBDII reader, please list the readout(s) here. It will help myself and anybody else help you diagnose the problem.