I bought a 94 8V back in August for a killer price of £285, it had proof of 84k on the block but just needed a clutch, picked the car up and on the drive back found the clutch was more than adequate but needed a new cable, quids in! Did the head as it looked a bit worn, new timing belt, water pump, thermometer, tensioner and all that good stuff and it seemed to be ok, this was completed around December and I had it standing until early feb when my insurance was due.
I have since been having a few problems with the car, one of which I just cant seem to shift. The engine was hunting pretty badly on idle so I replaced the spark plugs along with a new rotor, dizzy and coil (which had been failing) and it seemed to cure that problem, then noticed it was overheating on idle so replaced the engine temp sender which did not cure the problem - however noticed it ran cold at speed and overheated at standstill so put it down to a lazy thermometer which I am due to replace.
The issue im having is that the car, once hot, does not drive at all well under 3500 revs, if you do not rev the nuts off the thing it drives like its almost got no fuel, completely limp and stuttering (slower than my 1.4 ABD) until you get to about 3500 and it feels like a turbo has cut and and thing moves like a rocket. If you give it a blast for a bit the problem goes away until you stop again and it restarts the whole process. I have a hole in the exhaust just after the CAT as someone has bodged pretty badly down their and im going to get a CAT back system hopefully end of the month, im just trying to establish whether its the lambda thats gone of maybe the MAF as im getting no codes on the VAGCOM, although it was only a cheap eBay one.
Thoughts would be really helpful on this, thanks

edit: also, after taking the car apart to check the vacum hoses, noticed the oil breather was pretty gunked up and cleaning with petrol revealed a split in the hard plastic part - after sealing it up and the clean the thing ran much better and the problem im having took longer to occur... I am yet to clean the TB as it looked clean already.