P1250

[fri3dchick3n]

Alright. My car has been having this problem for a while now. Under a steady throttle the RPMs would drop to about 1k and start to studder and misfire. I would have to let go of the throttle and re apply the gas to keep on driving. Seems like it "resets" when I let go of the throttle. There is an overall a mojor loss of power, and randomly the car has trouble starting. Usually barely has to turn over to start.

So I took my car to the dealership on Tuesday at 7 am. They didnt get to it that day. So I left it there another day. They got to it for an hour in the evening. Found two codes: P1250 and P0300. Left it there for the night again. Checked on it this afternoon and they could not find what is wrong with the car due to too many modifications done to the car and an aftermarket chip..

I have 180* Tstat, Intake, Plugs, Plug wires. and I dont have an "aftermarket chip" in my car.

I do have the tab in the puel pump speed relay bent out, I did mention that to the dude at the counter. And they said that since I have done that, that it ruined my engine and I might need a new engine.

They kept the other receipt but it mentioned the computer "recording" the misfire when it had occured. It was at 5k RPMs @ 100% throttle. And he told my I over revved my engine too much. I told him the limiter was at 4k. But they didnt want to talk, just gave me my keys and papers..

What is the easiest way to check fuel pressure?

[2007gpgt]

A fuel pressure gauge hooked up to the schrader valve on the fuel rail. Sounds to me like your FPR is shot...

[fri3dchick3n]

I bought a new FPR and replaced it. Took it for a test run and the problem is still there. Should I still check the fuel pressure?

What are some other things should I look at. Fuel filter, pump. Electrical? Could coils cause this problem? Battery?

Since the new FPR didn't change anything, should I return it or keep it? It did cost me $141

[buck531]

The P1250 was the FPR which you replace. As for the P0300, that's a misfire. Does your service engine soon light flash while driving it? That code is a random misfire. Could be several things. Cracked spark plug, bad spark plug, bad wire(s), bad ICM. I'd start with changing the plugs and wires and go from there.

Just noticed you have new plugs wires. Which plugs and which wires? That and how old are they?

[2007gpgt]

Are you still gettin p1250 now that you changed the fpr?

[fri3dchick3n]

The P1250 code is gone now. I have AC delco 7mm wires and AL 606s capped at .059 I think. They have about 2k miles on them. I've always wondered if it could be the icm but asked an oreilly guy to test it for me and they can't.

But I did test my battery, it's about at 80%. has 440 cranking amps. Car starts like a champ, but is it good enough to run the car?

[rynoman03]

As cheap as plugs are i'd replace them. And the AC Delco's should be waranty'd if you have the receipt. Take them back and say you have a bad wire. You can also check all your coil packs for rust and take steel wool or sand paper to them. Unbolt your Coils look for rust and debris and do the same thing.

Or you could just get some junkyard ICM or coil packs. Do you know what cyl is misfiring ?

[fri3dchick3n]

I don't know know which cylinder it is. I do have cheap coils though, I replaced them earlier this year.

But I will get new plugs and try to get new wires. I'll see if I can clean the coils too.

Should I keep the gap of the plugs the same?

[darkhorizon]

Why did you replace the fuel pressure regulator???? If you were running rich I would have considered it, but it seems like that would be a completely random thing to replace when you have a misfire.... I mean check your plugs/wires/coils before you get that carried away.

The P1250 was the FPR which you replace.

What sort of crack are you smoking? I have never even seen a GM car with a fuel pressure sensor, let alone one that would have a code thrown for one... P1250 is an evap code, probably related to the gas cap being loose or something else screwed up with one of the solenoids....

I do have cheap coils though, I replaced them earlier this year.

There are very few cases that people actually get the correct SC coils it seems like...

[BillBoost37]

I googled the code. Interesting. I'd be wanting to know what year/model you have and look it up on the GM ESI disc. But it doesn't appear to have a thing to do with the FPR from the looks of what I can locate on Googy.

[fri3dchick3n]

Hmm. Well it is a 1999 grand prix gtp.

[fri3dchick3n]

It's a 99 Grand Prix GTP. I'll take a look at the site where I found the code

I just stopped by the dealership and asked them about that code, the service manager couldnt find it and said that it "could be a communications code or something. Or that all my aftermarket mods could be causing that code."

[fri3dchick3n]

Replace the spark plugs. They looked ok but still replaced. The car runs a lot smoother now but still has the misfire a little bit. I know the Wires/plugs are good. I really am thinking that it is the coils that are affecting me.

Will the coils affect the car driving like this?

Loss of power
Vibrations
Misfire
RPM dropping

[rynoman03]

Yup! Missfires do all of that. Coils are probably junko.

[fri3dchick3n]

Replaced the coils with proper ones. Better. But misfire is still there. Just driving and the rpms will drop and start to misfire/studder.

Any ideas?
Please help.
ICM?