So I started the car up this morning and saw my CEL light up, few seconds after codes started coming up in my NAV.. first it was P0304 then 301,306,303, 302, 305 and then finally the P0300 - Random cylinder misfire.

The car is running fine, no hesitating or shuttering although it did seem a little sluggish on acceleration, then again its like 100F here.

I've been to the dealer with CEL's before but P0141,140 codes about 3 times, they flashed my ECU, didn't help so they replaced my injectors, and then finally the exhaust manifold gasket which finally solved the problem. Never had the P0300's codes come up.

I'm thinking of taking it to the dealer again but I'm at 51,500 and out of warranty now, and since it's different codes I can't really claim that it's related to the previous CEL's. (They give 90 days warranty on their work if the same CEL codes come back, even if car is out of warranty)

So, any ideas guys?? appreciate the help.

 

No one?? Well I remembered one thing that might have cause the problem, last week I was out of state in PA and filled up at a Exxon station the had "ethanol enriched" fuel (15% ethanol) and I've been told before that ethanol can offset the CEL...
Well I'm gonna start with the little things, change the plugs, refill with some Shell premium and reset the light and see what happens.

 

Get your egr valve cleaned... I know it sounds strange but trust me on this one