Hesitates and stumbles on acceleration

[vv64581]

I bought a 91 300zx TT 5 months ago that had an engine /transmission swap 2 years ago. I'm told it has about 40 K miles on it. It ran perfectly until about 1 month ago. It started running rough at idle but ran great when not idling. A few days later it started running great all the time. about two weeks later it started running rough on acceleration but idles great. When not in gear you can rev it up and it sounds perfect. Only under hard acceleration does it stubble and hesitate. I read several of the posts and cleaned up all the electrical connectors. That didn't seem to help. I took out all the plugs and they look great. The turbo boost upon acceleration also looks normal and smooth. It's a beautiful car but almost can't drive it anymore because it hesitates so violently when I accelerate above 2500-3000 rpm's. Anyone have any other idea's? Could it be the turbo's?

[es.biggs]

Always a good idea to verify ignition timing is properly set.

[Ace2cool]

Is it an issue with the rpms of the engine moving violently or is it more of a chatter? May look into flywheel chatter and make sure everything in the drivetrain is in good working order.

[vv64581]

It appears to be from the engine . No chatter that I can hear.

[Z31toZ32]

run the codes, see if it spits a trouble code

[robomatic12]

You have verified the engine is running on all 6 cylinders with a power balance test? +1 on checking for codes

[catnipple]

my buddy had one that did the same thing n something with the timing caused n the spark plugs is what it was. there was like 2 spark plugs that were screwed n as soon as he changed them for cooler ones n tweaked the timing it ran great.

[vv64581]

Thanks for all the replies I will try these suggestions this weekend