2000 Impala LS 3.8L when start cold it runs fine until warm up and then RPM goes wild for second up to 1500 and back to 700 or just plain dies. It sometimes turns on CHECK ENGINE but after a while goes off. cod fault "low intake pressure". When unplug MAF sensor works just fine. And there is issue with maybee idle air control valve, not sure. Change thermostat and temp. sensor allong with new spark plugs with cables, Oxy sensor too, all OE.
ANY HELP PLEASE?