1998 Sunfire 2.2l code PO301 misfire cyl. 1

[phillipgr]

The car started running rough at idle. Check engine light came on, took to have code pulled came up misfire cyl. 1. Replaced wires,plugs,coil still running bad. Could it be the ignition control module or something else?

[GTP Dad]

It could be the ignition module but since the other cylinder on that coil is not misfiring then the chances are that it is alright. I would be more suspicious of the injector. Try swapping it around with another injector if the misfire changes to the other cylinder then you will need to replace the injector.

[phillipgr]

Checked injector it is okay. Do not know what else to do.

[GTP Dad]

Try a new ignition module if you haven't done so yet. That is really the only thing left to try since the injector checked out alright.

[phillipgr]

Okay since i replaced injector on cyl 1, Still gives same code unless i stop and get gas the light will go off for a little while and run fine. Replaced gas cap. Fuel pump and filter are new. Could it be the pressure regulator?

[GTP Dad]

Very possible but the first cylinder usually gets fuel before the other cylinders. I would clean the mass airflow sensor if you have one on this engine and see if that helps the problem.

[cprivitera]

Originally Posted by GTP Dad

Very possible but the first cylinder usually gets fuel before the other cylinders. I would clean the mass airflow sensor if you have one on this engine and see if that helps the problem.

Did this work? I am having a similar problem on my 1996 Bonneville. I cleaned the MAF Sensor first, and that didn't work. I'm thinking about changing the fuel injector next.