Heidi123

diagnosis rapid miss fire they changed fuel pump and fuel pressure regulator still doing the same thing any suggestions

dh1

need more information. How did you get the diagnosis? Pull the codes from the OBD?

I only ask because I wouldn't have gone into replacing the fuel pump and pressure regulator unless you had a diagnosis of low fuel pressure by measuring with a pressure gauge. While ultimately it could lead to a misfire, it's a pretty easy diagnosis with a pressure gauge.

Next thing I would check would be spark delivery and fuel injection. Is it only misfiring in 1 cyl? or Multiple cyl?

Let us know a bit more of what led to it, and what you have done to get where you are. Is it missing at idle, through the RPM range, under load?

maxxman04

agreed. what codes came up? misfire is caused by low spark, incorrect spark timing, low fuel delivery, low compression. replace the plugs/wires/cap/rotor, fuel and air filter.