Update had a new exhaust system put on so no leaks now. Sounds good. Showing no codes. But the backfire is still there. Can barely hear it when in overdrive but when not in od its very noticeable. Changed distributor cap and checked the routing on the wires etc... Thats all new plugs, wires etc... Appears to be running lean. Next payday im going to replace the fuel pump and filter. Gas gauge doesnt work so I believe its the float. Hopefully the fuel pump and filter will solve this backfiring issue. Im stumped with it.