Hi pyb!
Ummm Not completely!
If the wire is "jerky" when it starts to feed, and once you start to weld - it no longer feels like it's "jerky"...
Is this the actual scenario? I would also check the tightness of the gas diffuser, and the spool tension for any abnormalities... One more thing to check besides the the compression on the wire from the drive rolls is to check the alignment of the groove with other components within the feeder mechanism or if you have two drive rolls, check the alignment of the grooves to each other, and then the other components within the feeder mechanism...
If everything else checks out including the proper installation of all components associated with the wire feed system form beginning to end, then check first the installation of the liner and see if it is correct before changing the liner itself. I say this because some times feeder problems may be the result of some minor readjustment as opposed to constantly changing parts that in the long term, can drive up the costs of maintaining the equipment unecessarily. ;)
Everybody's suggestions beside my own, should lead you down the right path in solving your feeding problem so, when one troubleshoots a problem, one must take everything into consideration. :) :) :)
Respectfully,
Henry but, you can call me "Hank"