Loss of power on higher RPM

[Golf-tryout]

I recently bought a 1991 golf MK2, but almost immediately I noticed there was a problem when I pushed the car more then usual. It seemed to lack power, and it felt (and sorta sounded) like it was doing more RPMS then the meter showed, but the acceleration was painfully slow. Also when I managed to push the car up to 70 mph on fifth gear the speed began to decrease after only a few seconds and dropped down to perhaps 60-65 mph where it stabilized.

I appreciate any help on what might be the cause of this, as I myself lack almost all motorskills and sorta feel like an idiot for buying car that seems to be non-working. Also I'm not a native English speak so if anything is unclear pls say so, so that I can try and explain it again.

[Handeye]

Welcome to VWForum.

Does the car have an automatic or manual transmisson?

[Golf-tryout]

It has a manual transmission. I do however think it might have something to do with the exhaust being blocked because I noticed some coming out of the endpipe, which seems to be the "inside" of the muffler if what I've been able to find out on the web is right. Also if I look inside the endpipe I can see what appears to be a blockage about 30-40 cms in. So I will try to remove the muffler and see if it runs better then.

[bubba_vw]

ya thats sounds like thats it. but if it isnt, it could be the cat is started to plug up