1,8 K-jet runs like a pig over 3000rpm

Hi!
I have googled my butt off trying to find an answer to this, but no luck.
My problem is, i have recently taken my Golf out of the garage for the summer, but during the first, second and third testdrive i've noticed that it lacks power over 3000rpm's, it's like it is missing/lacking fuel or something. Does anybody here immediately know what to do, or could give me some advice on error-searching? before the winter showed up i changed the headgasket, could the camshaft be wrong? If so, shouldnt it run like a piece at all rpm's?
/Andreas

Ill just answer my own question..
The cable for the automatic choke was off, it probably just kept gushing gas through the coldstart-valve even at temp. Thanks anyways guys!