sputtering problem

[austin240sx]

ok, so this isnt about a sr, but i was hoping one of you could give me a hand anyway:help my buddy has a 95 mx6 2.5L v6. we got it out the shop about a year ago with some idle problem...the mechanic got in drove around the corner with a screwdriver, came back five minutes later saying he fixed it. then it started to overheat.... three thermostats later and colder radiator fluid (and winter) and his car is no longer overheating. now, when its cold, he can start his car and get a nice little cloud of black smoke and the smell of gas. today, the mx started to sputter and lag during acceleration between 2000k-4500k rpm's. any ideas?oh-yeah, last week we had the fuel pressure tested supposed to be 38 psi, was 39... any help?:help thanksjustin

[DriftBandit]

I would make sure you are not running rich. I was running rich, my idle was very low and unstable, black smoke out of the exhaust, and sputtered like crazy at constant throttle. An adjustable FPR fixed all the problems.

Just something to think about,-Jon

[NISTECH]

as with nissans its probably air flow meter,Coolant temp sensor, or O2. If you can get the specs and wiring diagram all those can be tested easily.. I am not familier with mazda's so I am not sure if there would be any other fuel control devices for it.