1998 dodge ram project

My bet, head gasket blown cylinders 5 & 7 blowing the compression back and forth between them.

Pressurize cyl #5 with air from your air compressor. Pull the plug on cyl #7 and see if the air comes out there.

At least it's only one side to pull the head and put on a new head gasket.

Can you imagine how that screws up the readings to the computer and the computer is trying to compensate going rich lean, rich lean trying to figure it out.