Cylinder Misfire codes
 

97 Grand Cherokee Laredo 4.0L 4x4

A month ago I got a code for cylinder 6 misfire and the auto place said change your plugs, wires cap and button. Everything was new except the plugs so I replaced those and the code went away for a month.

A couple of days ago I got codes for misfires in 3, 5 and 6
For over a year Ive been dealing with a bucking/surging type effect and now I believe this is because of the failing valve springs. Anyone have any experience with something like that?

The auto place said the codes are pointing to the valve springs and said it sounds like your springs are collapsing.

Whats the likely hood my cam shaft will need replaced?
I plan on replacing the springs, rods, lifters, timing chain, sprockets, cam and crank sensors

What else can I pay attention too when I open the motor up?