J
I'd give the engine flush a try first and see if it helps, with the v6 it's possible to take off the Cam covers, remove the cams and take out the HLA's then service them, but it's a fair bit of work.
When I rebuilt my engine last year, I stripped the HLA's down, there were mixed reviews about whether this is a good idea or not, but it wasn't all that hard if your careful, they key is to make sure you soak and pump them with oil before putting them back.
The reason they get sticky is old oil gums up inside them, then they stop compressing and pumping the oil through themselves, regular oil changes can reduce the problem.
Jono
