Truck has started a miss/backfire I thought it was some bad gas ,but I have since put in a new tank and some gas treatment. Put it on a scan tool today and no codes or misfires showing on the pcm??? Truck is obviously misfiring or of the such. Anyone know where to start on this egr was showing to be off while we were driving it but I assume that is normal or could an egr even cause something like this?? Also anyone ever had a pcm go bad? The reason I ask is because of it showing no misfires?.

 

no codes? is the fuel pressure good. i would check that first. it is easy with a good gauge. then if that is ok then i would pull the plugs to check them out. if the have a soot on them then replace them. oh yay also clean the maf to.