Hi all,

I recently had an engine overheating problem which was caused by a cracked impellor in the pump. The mechanic replaced it and replaced a number of other things including the timing belt (kit), thermostat, radiator cap, by-pass hose and ignition leads. (2004 MkIV Golf)

Driving it home from the mechanic (less than 500 yards), I noticed the engine seemed to run a little rough at idle. I took it for a good run today (about 70kms up the freeway) and noticed a number of problems which were not present prior to me taking it to he mechanic.

Firstly, the engine runs a little rough at idle (it isn't really rough, but gently shudders). When I put my foot on the accelerator I get a very long lag before the engine kicks in (several seconds). In second gear the engine becomes jerky after the gear change until the revs raise above about 3000ish (not entirely certain though). Finally, I was accelerating in 5th gear up a long gentle hill (increasing from 100kph to about 110kph) when the engine became very jerky. Jerky enough that I backed right off and moved to the far left lane.

Obviously my first thought is that the mechanic has stuffed something up, but I've not got a lot of idea what it might be. Can anyone give me an idea of what might be happening and whether you think it might have been caused by the mechanic?

Cheers