: rough idle at start-up



1999caddy
01-14-05, 02:18 PM
I just replaced the EGR valve on my 1999 Deville about 2 months ago to fix a stalling problem and it worked. I had rough idle at start-up before I replaced the EGr and seemed to go away. However, the rough idle came back today. It goes away after the car warms up. My "sevice engine" light comes on during the rough idle and gives me a mis-fire code of P0300. The "sevice engine" light flashes in the beging and stays on steady as the car warms up. Any suggestions. Can the new EGR be acting up?

mcowden
01-14-05, 05:42 PM
How many miles on the car? Did you just have the fuel rail replaced by any chance? You might want to search the forums for "fuel pressure regulator," because that's a common problem and can cause that symptom. It's a pretty simple fix if that's it. There are lots of options here. Let us know any more details you have and somebody will probably be able to point you in the right direction.

Good luck...

M C
:cheers:

andy2175m4
03-08-05, 07:45 PM
My 1999 Deville with 60,000 mi is doing the same thing. I took it to the dealer, and $160 later, no change. I have pulled all the injectors and they look clean, so it may be the fuel pressure regulator. Where is that little goodie and how do we fix that ??

thanks

Andy

How many miles on the car? Did you just have the fuel rail replaced by any chance? You might want to search the forums for "fuel pressure regulator," because that's a common problem and can cause that symptom. It's a pretty simple fix if that's it. There are lots of options here. Let us know any more details you have and somebody will probably be able to point you in the right direction.

Good luck...

M C
:cheers:

mcowden
03-08-05, 08:38 PM
The fuel pressure regulator is on the fuel rail that you must have removed to take out the injectors. It's the only thing connected to the fuel rail that has a vacuum line attached to it. Small metal canister with a hose connected to it. To test it, remove the vacuum line with the engine running. If you see fuel dribbling from it, it is ruptured internally and in need of replacement. If your car is running rough, though, it is probably not the FPR unless it is hard to restart when it's hot or seems to be running rich all the time.

Have you checked for trouble codes? What are they? If not, search the forum for OFF WARMER and you'll get plenty of hits about how to do it. Post the codes here and somebody can tell you what's going on and how to fix it. I would guess plugs and wires may be in need of replacement, but that's a ballpark guess without hearing the codes.

Let us know...