hey, sorry to hear of the troubles.

there is a lot of info in the maintenance and info section at the top of the mk3 section... try there. (there is a pic of an 8v engine bay in the common faults sticky) use the search function, usually turns up something.
Replacing any split pipes is a good start. check plugs, leads, distributer, coil... could be quite a few things....

sorry if that isn't much help.....
P.S. welcome to the forum