Sea-foam, MMO, or fogging to help sticky valves?

[Mark W.]

Last fall I purchased a 28 Phaeton which has not been driven in a long time, it seems to have the problem of backfiring and bucking that I would atribute to sticky valves.

My question is whether MMO in the gas, sea-foam, or "fogging" the engine with penetrating oil will help this issue. I hate to tear into the engine when the weather is finally cooperative for driving it.

Any thoughts?