996 Miss Fire on Right Bank, After Left Bank Coil Change

[McSwerve II]

Evening all. A coil failed last night in my early 996. As I had a spare I put it straight on (left hand side).

After a quick test drive all seems well, but then the CEL came on. After reading the fault codes its showing misfire codes on all the right hand side cylinders.

Any thoughts? I’m probably going to start with the plugs and coils on that bank, but I’ve been reading about Variocam Solenoid failure, as its to the one bank.

Seems strange its happened after doing something on the other bank though.
Any thoughts gratefully received.

[Rockster]

The engine can misfire from a failing VarioCam solenoid/actuator but there should be at least one pending code pointing to the VarioCam system. I would not dive into a VarioCam solenoid/actuator R&R just on misfires on one bank alone.

More likely you disturbed something in your coil R&R. I'd check connections, hoses, etc. Check the VarioCam solenoid wiring too.

Without knowing the car's history it could be that all coils are bad and in replacing the worst one, this now has promoted the others to the bad level.

Generally unless a coil is bad out of the box when one coil needs to be replaced they all should be replaced. Otherwise one can spend the next X days or months doing one at a time as he works his way through the coils going from the worst one to the next worst one and so on.

[McSwerve II]

Thanks for the input.

I ordered new coils and plugs last night. This morning no check engine light!

I’ll still swap them all out though, as the others I could see looked on their way out.