I have a 99 Mazda b2500. Having issues when I'm driving it wants to almost stall (feels like when you run out of gas). RPMs go down, when I give it gas it goes. There's no black smoke coming out of tailpipe. This only happens when I give it gas. It will go several days to weeks in between doing this. Usually it only happens once or twice a day, but this morning it happened 15-20 times in a matter of 5-10 mins. Fuel pump and filter are 3 years old. Could this be a fuel pressure regulator?