running rough through rpm range

my buddy has an 87 300 Z and the rpm's want to jump around when he accelerates, it sucks gas badly, and on cold mornings it idles rough when he starts it and then it dies. any ideas?

i forgot to mention; it is a 3.0 V6

uh yeah... they only came in 3.0 v6's for 12 years... anyway... by 'jump around' you mean rev up higher than it should be when he accelerates? could be a slipping clutch... put it into 4th gear where it's at 2k rpm and floor it... if the rpm's go up without accelerating, his cluch is on its way out/dead.... the bad gas mileage could be a number of things... has he done a tune up lately? (air filter, fuel filter, plugs, injector cleaner) that could be the cause of the rough idle/dying when it's cold... little more detail would be helpful

the bad gas mileage and rough idle is most likley due to plugs and filters, replace all those and that should help. please explain the first problem better.

the fuel filter; injectors, plugs, air filter, oil & filter and all has been changed. if i remember correctly he said that it kind of stumbles as the rpm's get higher and the way he described it is that it kind of skips to higher rpm's. It's an automatic so the clutch problem is out of the question, and he said he's had the transmission checked out, but he said no shops will work on these cars so he couldn't get anything else diagnosed. Thats about all i know to tell you. I know it could be one of about a million things with these cars; but i appreciate any input.