It seems like an electrical issue, ive checked all of the fuses and they are good. The car will start and run fine until you get on the gas, it totally loose power and almost die and a few seconds later it will run normally and sometimes the radio will turn off and then on again. Where should I start trying to diagnose the problem? Thanks in advance.

 

Have you checked to see if any codes are stored in the ECU?

 

does the car fall on it's face at hard acceleration? can you ease into a fast speed?

 

Mahjik, I am running a Power FC, if that makes any difference.

SINxSELEKTAH, That sounds about right, If I ease into it it will run good. It almost feels like a ground wire is loose or something. Did you have the same probblem?

 

Drove the car again today, checked all of the grounds they are on good. Once I get on the power it feels like it is slipping (can't be the clutch cause it has a new one) and it will backfire and shoot out a big buff of black smoke, it will run fine at low rpms. Any ideas?

 

What is all on the car? Is the PFC tuned? Did this just start happening out of the blue or was there work done on the car and then this started after the work?

If you believe it's electrical, I would start by checking the wire looms on the driver's side of the engine bay. If for some reason you've rubbed through the fender liner they can get torn up.

 

It just started happening out of the blue. The PFC was tuned, the car has an aftermarket SMIC, downpipe, mp, exhaust, other that that its pretty much stock. I need to get another postitive battery terminal, i don't think that is the problem but we will see.

 

Im 99% sure the positive battery terminal was the problem, it was corroded underneath and that little bit made the connection not very good. Mazda does not sell the terminal seperatly, I would have had to buy the whole wiring harness to get that terminal so I got a generic terminal and bended the tab up and it fits like a glove. Car now seems to run great, thanks for the help Mahjik.