Im getting some pretty good back fires now that I'm running e85. I havent had the car on a lift yet, but I think there is a small exhaust leak in the x-pipe, and the back fire seems to come from under the car. I dont know if this might be caused from an exhaust leak, i.e. the exhaust hasnt had enough time to dissapate heat and the fresh air at the leak is making the back fire. Maybe plugs? Im running Tr6's gapped at .028-.030. 21-22 psi. Car makes good power and the back fires werent happening like this on the dyno. It had a small back fire, nothing like this though. Could this be tuned out with out risking running lean? It happens when I shift 3-4 or when I let off in 4th. Basically on decel at higher rpm under good amount of load. Thanks in advance. All relevant mods in sig.