Hesitating and RPMs are jumping around

What is your question?

I have a 94 Chevy K 2500 as I'm driving down the road and I give it gas on a hill or even on a straight away it will hesitate and stumble and as I'm climbing Hills the RPMs will reach 2,500 and then drop down to 2,000 RPMs and jump up to 2700 RPMs but my miles per hour will rapidly decline even if I put the pedal to the floor the motor will just hesitate and struggle even more almost like it is trying to die I have replaced the cap to the rotor new spark plugs new ignition coil wires new idle air control new EGR solenoid none of which has fixed the problem does anybody have any suggestions that can help me get my daily driver back on the road and running correctly again

What makes this problem better or worse?

Motor can be warm or cold still hesitates and stumbles

How long has your 1994 Chevrolet C2500 had this problem?

About a month