Misfires !

[INTHERED]

A friend of mine has a C5 TT 427 that is in the shop for a new tune. The new tune guy noticed that the engine is throwing a p0300 code but the misfires are is only on cylinder #5. The shop checked the normal stuff plugs, coils, injectors and compression and they can't make the p0300 code go away. The original tuner sez that the cam he installed is the cause of the problem and that the p0300 code should be turned off like it was in his original tune. I guess my question is could a big cam cause false misfires on only one cylinder ? Or would it tend to be more random across all the cylinders ?

Thanks >>>>> INTHERED

[12secSS]

It would be all the way across, not one cylinder specifically. How many misfires are seen? Did the new tuner do a cylinder balance check? What did the plugs look like? What does the scan reveal?

[INTHERED]

It would be all the way across, not one cylinder specifically. How many misfires are seen? Did the new tuner do a cylinder balance check? What did the plugs look like? What does the scan reveal?

I really do not have any of the shop data. Iam just trying to do some research for my buddy to see what makes sense on how to proceed. Maybe the PCM or its wiring is the next option ? We really need to compare a couple of cylinders on a scope.


INTHERED