i have been having a lot of hesitation.

What is your question?

i have been having hesitation during acceleration and when I'm been going uphill.before it started I have my car to spit,sputter and quit on me with the check engine light on, waited bout 20-30 min.car would start again.in the past year or two I have had the ecm,plug wires,spark plugs, all coils replaced,both oxygen sensors,crankshaft sensor, camshaft sensor, starter motor, etc.my car has an electronic egr valve how does an egr valve act when it's bad,what could be causing my hesitation and my engine stall problems,engine stalls tend to happen when the weather is warmer.