| Use Conzult Software to read the Fuel Trim and see where they are.. it could be the Banks are running Offset mixture.. ( various Causes Possible ) and when Cold, the Trims ( lack of O2 Sensor correction ) is not giving enough fuel to both banks.. Or you could get ECU Talk ( Free, but you still need a Conzult Cable ) and watch the O2 Sensor Voltages as the engine come to life. The Sensors will not directly show voltage untill the Exhaust system heats up.. Even though they have heaters in them, it takes some time.. However, the O2 Sensors will come to life and should be giving you a ~.6 to.8 Volt reading as the Engine does a warm up.. AFTER the coolant reaches a certain Temp ( I forget where ) the Mixture will then go to Closed loop and start using the O2 Sensors.. My thoughts are, you might have one bank lean ( Less than .4 Volts ) during warm up and it is causing a Stumble.. Some causes are Air Flow differences per bank.. Any way, I'm thinking software in needed before we start pulling Guesses of the shelf as to what it might be.. Cj
|
