Help - 1984 GTI running rough

[callwaygticab]

Hello, would appreciate any advice you can offer. Bought this GTI not running too well. Changed plugs, wires, cap/rotor/fuel filter, timing belt, engine oil/filter, coolant, cold start regulator (on front), and she starts right up, but is very slow to rev and bogs down at full throttle. I have checked fuel pressure at fuel distributor and it is 50psi with valve open and reaches 72 psi with valve closed. Ignition timing is correct. Compression test shows 150 - 170 psi across all 4 cylinders. Yet, revs remain slow and top rpm under load is 3,000. As car warms up, seems to get worse. Have I got a fuel problem, plugged cat., or something else??? Thanks for reading.

[1meanBunny]

could be the cat but the exhast would smell like rotten eggs and if it dont work check you thermo time switch on top of the front water neck that would be my next guess

[stevethefolkie]

Actually the cat matrix could have collapsed OR a baffle in the muffler could have come loose - either would block the system and give your symptoms - while the car is running check for exhaust flow while a friend gooses the throttle - compare to a similar vehicle idling nearby -

Another thought is a bad ignition advance - (you can check that one with a timing light) - or - a wiped cam shaft that's not allowing the exhaust valves to open all the way (in other words, the lobes are damaged) -

Steve

[vwcarnut]

I had this problem as well. Check for a Vacuum leak. All the hoses, plastic lines, and around the intake manifold & throttle body.(soapy water mixture works well & is safer than carb cleaner) Also look to see if you haveany of the o-rings on your inj. leaking. Hope this helps.