Its a 92 chevy 3/4 ton four wheel drive with 350 engine and manual transmission. went out and started it, it ran for four or five minutes and then just died. it will start but will not hold a idle at any rpm it will run as long as your moving the gas petal but as soon as you hold at any rpm it will die. i have replaced pick up screen, fuel pump, fuel filter, tp sensor, iac sensor, egr valve, test the map sensor its okay, replaced the ecm, checked all the vacuum lines, plugged off the master cylinder, pulled all plugs looked good, all fuels are topped, all new cap and rotor, plugs and wires. no codes are being shown.