I have a 1996 Z34. Owned it since new, of course it has had the typical issues.But still love the car. I have had miss problems, have been letting it go because I didn't have time to put in 3 hours to change plugs/wires. Died on me recently, ran like hell and wouldn't go. Had it towed back, replaced wires and plugs. When I started it up purred like a kitten, but when I took it out got to about 30 and feels like it is towing a house. Settled on cat must be plugged and might have been contributing to my miss condition that has plagued me for some time. Started it up tonight again after a few weeks on vacation. Idles well, but still not accelerating above 20/30 mph. Looked under car and didn't see cat glowing, didn't drive it far though. Thinking of just cutting off the cat and see what happens, would it be better to cut off or disconnect pipe at header connection or other ideas?

230K miles, never changed cat.