GM-GMC: Hesitation, egr valve position, egr valve position sensor

Question
My 1998 Chevy K1500 4x4 5.7L SFI has a bad hesitation when i stomp on it. Sitting in the driveway in park i can gun it and it has no hesitation. Out on the road in gear when I do that it stumbles. As it speeds up and gets ready to shift it seems like it pauses and then jumps into the next gear. I put new plugs, plug wires, cap and rotor on it and i still have the problem. I checked the EGR valve position sensor, between terminal 4 and 2 i have 5 volts with key on. I also checked the continuity between 2 and 4 and 1 and 5 with key off, both show a closed circuit. My next step is to look at the catalytic converter. Could it be stopped up? Can you help me? Thanks

Answer
Is it possible that you have a transmission problem?  Try selecting a '2' or second gear and go for a drive.  See if the engine hesistates then.  This stops your tranny from shifting out of second and may give you a better indication of how just the engine is running. If you suspect your cat being plugged, try unbolting your exhaust at the headers just enough to drop it an inch or two. Go for a quick drive to see if it stop the hesitation and funny shift.  I will warn you it will be loud loud loud and you don't want to drive it for too long or far like that, too much heat coming out the headers can melt things.  But it will let you know if it is your cat.
Hope this helps