I bought this Chevy S10 brought it home drove it an hour check engine light comes on for P420code which is converter they took the converter off and straight piped it also the p300 code was coming on so we did full tune up rotor button cap spark plugs wires and still p300 code also changed the ignition coil and the ignition module beside the coil any help would be appreciated. The y pipe underneath is bent bad could that be clogged and causing both code to come on
also it will run fine and drive good until you get to a stop sign or a red light and then it looks like buckle down like it ain't getting gas or out of gas but then once you drive it back up and start driving it drives fine runs clean and then once you let it idle and park it and let it idle it'll Grumble down and shut off