I have a 92 GXE and when my engine warms up after about 10-15 min. it starts lunging and i get a loss of power, but after it gets past 3,ooo RPM's it runs normal. i've checked a few things and it isn't the EGR valve, fuel injectors, coil on plugs, or water temp sensor. if you have any ideas please help. thank you

 

Do a search on the AAC valve. Mine's doing the same thing. I'm going to try and replace it this weekend. I've replaced a similar valve on a Chevy truck, called an Idle Air Controller, also known as an Idle Control Valve. They can do that. It started bucking, stalling, missing, had a fast and/or erratic idle and smoothed out only after 2,500-3,000RPM.