same thing with my car here is how i fixed it

change 02 sensor
new plugs and wires
change oil
new air filter
clean IM with cleaner-car will run like crap for about a week then back to normal
run 1 bottle of super concentrated fuel injector cleaner on top of a full tank of 93
and change your valve cover gasket im sure when you got your vc done by bucky like did you just took the old one off took the gasket off and put it on the painted one yeah your plugs are wet

do all of this and you should be back to normal