jonesvlk

I have a 2001,Grand Am 2.4 duel overhead cam, with 160,000 mi. Engine running rough at idle and above. Did an OBD2 scan and it reads Code 0300, random misfire. Changed the plugs and boots, no help. Freeze frame on obd2 checker says fuel system cl 1, then fuel system CL2 fault, Do I read this right that cylinder #2 is at fault? Did a NOID lite chk and all seems normal. Resistance check with in limits. What next. Thought maybe the MAF sensor , but shouldn't that show up on the OBD2 checker? Any help on this is greatly appreciated. Mary

J-Ri

There's a 25% chance it's cyl #2.

I would think that the scan tool is saying "Fuel system Closed Loop on bank 1". Since there is no bank 2, that is probably why it's saying there's a fault, my scan tools (Genisys and MT-2500) both would say "no" or "disable" instead of fault, but all are different. With it running, look at "misfire data", or it may be under engine data or something else. It should show a misfire counter for the cylinder(s) that is/are misfiring. You can also use "Mode 6" on a generic scan tool to show the misfires, but I couldn't tell you the TIDs or CIDs off hand.

Coils and ignitions module are both common problems on these.

I could be mistaken, but I don't think the 2.4s use a MAF sensor to determine airflow, they use the MAP sensor to determine load which directly translates into airflow.

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You see "Fresh oil, loose gravel"; I see "Free undercoating"