Car is a 2009 Chevy impala. Engine code p0455 is the only code my car shows. I have already had a vent solenoid replaced. It was the one by the gas tank that was about a year ago now. No issues since. In the past few months many things have started to happen that don’t seem to line up with that code. The car idles so low it dies sometimes. About two times I have gone to turn the key and the engine is turning but doesn’t turn over fully. By the second try it starts. When I am driving it feels like it’s losing power sometimes. And then I have gone to Accelerate and also while I’m driving the same speed ... my car dings and says traction control. Within a minute this goes away. When I start the car it always seems to jump forward. Not sure if that’s relevant. Would like any suggestions.

  • Well it definitely has something to do with your evaporative fuel system. From the code and the symptoms. You will need to have a workshop take a look to see if they can find your EVAP leak. Sep 11 '18 at 14:48
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    You have another problem P0455 will not cause any noticeable driveability problems.
    – Moab
    Sep 12 '18 at 22:27
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    You have triggered pet peeve #482, the misuse of the word random and its derivatives. "engine dies randomly" OMG, that's so Not random, it dies because of a specific problem or miscellaneous problems. Engine dies sometimes.
    – Alaska Man
    Apr 4 '20 at 23:11

Likely should replace the complete fuel pump assembly. Common issue with GMs in that age range. I just fixed a 2006 rendezvous with the same symptoms, but no DTCs. 340K miles, original(or dealer) pump assembly. The inside of the tank was pristine. The inside of the FP assembly had about a spoonful of fine, reddish particulates clogging everything. This simple two-person 1 hour repair also took care of a flighty fuel gauge, hard starts, poor idle, poor acceleration. etc. You also will need to clean or replace the spark plugs as they are surely fouled. Your performance will gradually increase as you drive, probably as excess loose carbon deposits and the like burn out of the motor. Recheck the plugs after a few days. Now that it runs better, the next weakest component will fail. For me it was the right bank #1 HO2S, or oxygen sensor. It was fouled with a lot of carbon from running so poorly so long. Good luck.

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    Instead of just replacing parts because someone on the internet said they should, how would the user go about verifying the pump is bad without dropping the tank? What diagnostics could they do to help figure out if this is the issue? Replacing parts on a hunch is probably the worst way to go about fixing a vehicle. It usually takes longer and costs more to get it fixed. Sep 12 '18 at 11:53

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