Not to hijack, but can bad O2s or plugged cats cause this to change? After my 93 tune, it didnt take much throttle to get the verter to unlock but last few months its been taking more...

 

If he's actually feeling a misfire and is feeling the truck jerk or shake, then it's a true misfire, meaning something mechanical is bad.
Even if the converter setting was too low, no matter how low (as long as it's above stock), the truck will not shake.
Things to check for a misfire: bad plugs or cracked ones, wires, injectors, coil, etc.
Also, I've seen a weak or bad o2 cause drivability issues.