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10-31-2006 04:12 PM #1
P1250 fault code (fuel) misfires, rough. any idea?
For a while now my car has been running rough at times. Sometimes it seemed as if cylinders would shut down. I checked the fault codes and it was misfires in 2 cylinders. I replaced all the spark plugs, and it was actually fine for about a week, but now the behavior is slightly different. The idle will be really rough, but if I rev it up a bit, that will sometimes go away. Feels like it's a few cylinders short, but sometimes reving it will have it go away. Other times it sticks around until I turn off the car for a few minutes, then restart it. The fault codes are:
P1250 --- Fuel level too low
P0300 --- Random/Multiple Cylinder Misfire Dectected
P0304 --- Cylinder 4 Misfire Detected
P0305 --- Cylinder 5 Misfire Detected
P0306 --- Cylinder 6 Misfire Detected
Seems the word 'P1250' has never appeared on this forum, according to my search. Anyone have any idea what the cause of this is? At first I was hoping it was the cam shaft sensor that's common, but I did not get that fault code. Could it be as simple as a dirty fuel filter? Could the fuel issue be causing the misfires? I'd think so. Could there be some other fuel delivery problem? Yes, the gas cap is fine. :-) Any tips would be appreciated...
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10-31-2006 04:39 PM #2
fuel filter is possible
it could cause a fuel pressure drop and lead to misfires, fouled plugs, etc. i'd definitely check that first but don't necessarily bet on it. one reason i say it is that a fuel delivery problem would usually show up first at high power/rpm (when flow is the highest).
another thing to check is the ground strap between engine and chassis, maybe clean everything with a wire brush and retighten. look at the voltage gauge when the engine is running, too.
06-30-2011 01:59 AM #3
06-30-2011 08:28 PM #4
- Rio Rancho, NM, United StatesMember No: 137549
- Join Date
- Feb 2006
- Rep Power
The P1250 code might be a plugged fuel filter or a flaky fuel pressure regulator. A plugged up fuel filter is tough on the fuel pump and can cause all kinds of weird rough running/misfires. Often this stuff is intermittent, temperature, and fuel level related. Also, when the DME detects a certain amount of misfiring (not sure what the limit is) it stops trying to fire that cylinder. Shutting off the car and restarting clears that sort of fault. Any chance your getting crappy gas? Probably not, otherwise it would happen on all cylinders. It's interesting that the misfires are limited to 4/5/6. Hmm, 4 5 & 6 are on different O2 sensors than 1 2 & 3 aren't they? (dual exhaust pipes to the back) I believe 1 2 & 3 are referred to as Bank 1 and 4 5 & 6 are called Bank 2. This Bank 1/Bank2 distinction includes more than the exhaust system and includes other DME functions. After replacing the fuel filter I'd take a look at the Bank 2 O2 sensors and the wiring to the coil packs for Bank 2. You could try swapping the O2 sensors & coil packs between Banks 1 & 2 to see if the problem moves too.
10-19-2013 11:11 PM #5
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