this was a week ago, the check engine was on for 3 dayslight now it has not appeared again
It's probably nothing. Check engines lights come on for ridiculous reasons. I'm guessing what it would mean was your fuel to air ratio was lean and that's what made the light come on. It could do that because you need your injectors cleaned and or maybe there was a piece of carbon in there for awhile which made it lean out a little bit in turn turning your check engine light on. If your injectors were super dirty your car wouldn't run. I don't worry about check engine lights myself just because they'll come on for a stinking exhaust leak or whatever. They're quote annoying. I was kind of taught the old school way and just listen to your engine. If there's something wrong with it you'll hear it. I'd suggest though go to wal mart, autozone, whatever you have and get some injector cleaner. They have a bunch of different kinds you just add it to your tank of gas when you are about to fill up. That'd clean them out. If you have problems finding it just ask the guys at autozone or advance, napa I don't know what kind of auto parts store you have. But normally they're willing to help you out. And theyll steer you the right way. Hope that helps a little.
There is still a code stored in the PCM! Need to know the YMM (year,make and model) to give an accurate diagnosis! Also what was the alpha numeric code? There is no such thing as a left bank it is either bank #1 or bank #2. ADDED: Thanks for the additional info! Are there any performance related issues ie. poor acceleration, hesitation, rough running?
The problem may be in the exhaust system, such as a bad flex coupling in the header pipe, or just be caused by a fuel filter that needs replaced. Now the fuel filter replacement is easier (and cheaper) then an exhaust leak to fix. But if you have noticed an increase in engine noise suspect that you have a leak some place between the engine and the front O2 sensor.
