Volkswagen: 1992 jetta runs very rough @ 2500+ rpm, jetta 1, filter cap

Question
I'm working on a 1992 jetta 1.8L 8v (144,000 mi.)for my nephew. He recently took a 1600 mile trip and about 400 miles from home the car gradually became more and more sluggish. Finally the car would not rev beyond 3000 rpm and ran extremely rough from 2500-3000rpm. compression checks on cyls. 1-4 @ 150,140,140 and 150 respectively. Replaced the timing belt and reset timing to factory settings,replaced air filter, cap, rotor and plugs...... still runs the same. Seems to be running very rich when it starts running rough. Are these acceptable compression readings? Any other ideas?

Answer
Hi Steve,

The compression readings are absolutely fine.  Did you replace the wires as well?

Check all of the vacuum hoses, they tend to rub on each other and create leaks.

Next, replace the fuel filter and PCV valve -- they will cause rough running, than put in two bottles of very good fuel injector cleaner.

Let me know how this makes out.  If you still have a problem,  the next thing to diagnose is the fuel pump.

Good Luck,  we'll get it going again!

Ron