GMC Repair: shudder at highway speed, torque converter clutch, gmc yukon

Question
My 1997 GMC Yukon kind of shudders or pauses, feels like a bump, at highway speeds/cruise control.  I've changed the plugs and wires, fuel filter, and run fuel system cleaner through it.  The RPMs on the tack are not affected by the bump in the system.  Any suggestions?
Thanks

Answer
Hi
You did not say for sure, did you change the Distributor cap and distributor rotor?
If not try that first.
Then does it do it at cruise regularly, meaning while in cruise, does it do it twice a minute, or like that or does it do it only once per cruise cycle after speed is reached?
If the latter, only once per cycle after speed is reached, it COULD be the Torque Converter Clutch (TCC) shuddering
This would happen ONLY when the Torque converter clutch is applied (In fourth gear at steady speed).
I would try the Distributor cap and rotor first (If not already tried) If so, Take it to a repair facility your comfortable with and get them to watch the "Misfire Data" with their scan tool while acting up to "catch" the cylinder(s) that are misfiring. This will aid in Diagnosis.
Could then be looking at possibally an injector(s) for that cylinder(s) or a mechanical problem for the affected cylinder(s).
Please if more help is needed or requested, please let me know I'll do what I can to help.
Thanks
Paul