hey i have a 1990 na 300zx, and when i change gears it tends to hesitate a little then go again, it generally only does it below 3000 rpm. now last time i checked it had a crank angle sensor problem and knock sensor, could this be the problem.and it does it on all fuel octanes..? can any one help
I had what i would call a bad "flat spot" between 2K and 3K rpm when my O2 sensors needed replacing. That range was horrible. Rough. No power and engine sounded uphappy. Push past it and she was sweet. If that sounds like what you're getting, try disconnecting your O2 sensors and going for a drive (which is fine and besides crap fuel econamy, wont hurt anything) If you loose that flat spot when they are disconnected, you know its the O2's that need replacing.
hehe na its a manual.. no its very strange. if you drive it in a high gear say from 700 rpm all the way up to 7 its fine..just when you change gears around the 3000 rpm mark..im thinking its running a bit rich or something but i still get a bad crank angle sensor..so maybe its not advancing as quickly as it should and not fireing the fuel properly. i have been told that it usually gives a little black puff of smoke out the exhaust when i do it.and this is even under a light foot
ah forget everything i said then lol if its any help, mine is running massivly rich but doesn't do what you're descibing at all.
definitely try o2's and have a search. I also had the exact same issue a while back. Went about replacing things that were probably fine such as fuel reg. and dampner. Turned out to be a combination of bad o2's and det. sensor circuit error (was result of dead sensor, not wiring). Try the ECU diagnostics posted in the tech section edit: the o2's and det. sensor circuit error code will both cause you to run richer than you should btw.
