To have been getting a persistent P0303 (cylinder 3 misfire) code.

About 2 weeks ago I replaced the valve cover gaskets, plugs, wires, and EGR valve. After putting it back together it was idling rough. I assumed the computer needed to "relearn" the idle and followed that procedure. Upon test driving I got the P0303 code. I started chasing down this issue by replacing the cylinder 3 plug again, replaced the plug wire again, and the center coil pack. The code continued. I ran injector cleaner through with no response. The way it is idling with surges would point me towards the idle air control valve, but the P0303 code is throwing me off. It was running perfectly prior to the valve cover gasket change (other than leaky gaskets).

Any suggestions?

 

Check injector #3 harness and hope it got disconnected when you were working on the engine.

 

Hi Airmed, ]
I had the samething happen to me and was wondering about your vacuum hoses on the top of the plenum. Their should be two hoses mine were reversed. Let us know how ya make out...

 

Last night I took everything back apart, for the third time. Checked every plug, wire, connection, etc. I put it all back together and erased the code. After testing everything is working fine. I'm guessing it was a bad connection. I don't know, just glad its working. Thanks everyone for the input.