I have the po431, and po421 codes showing on my reader.

Question

I have recently changed Sparkplugs, air filter, and purge vent valve.Had to remove the air intake to change plugs, installed a new gasket.The engine floods or tries to flood on warm startup, and if left Idleing tries to stall out after a few minutes.Otherwise it runs fine over the road with no power loss.

Answer 1

Hi there,

These codes may be the result of a rich fuel mixture. I would check the mass air flow sensor. This sounds like a possible problem with the maf sensor showing to much air coming in and flooding the engine with fuel. Try unplugging it and see if it starts any better. If it does, replace the sensor.