Another Q on this build. I have a 5.3 flex fuel in a z71 suburban. I found that I installed a 6.0 head gasket set. I know the bore is a bit bigger on the 6.0 but would it cause rough idle?

 

Possibly, but if it’s not setting misfire codes, it’s unlikely that it’s the cause.

How long has the engine been run since the head gasket replacement?

If it’s setting codes for anything other than misfires, pursue those codes first.

 

I’ve barely run it considering how rough it is. I did throw random misfire code 0300 I think. I replaced the fuel injectors with a set of no name generics so I have ac delcos coming. Also got a fel pro intake man gasket set in case there’s a leak. I was just concerned that the head gaskets could be the issue