How close are you to your next oil change? The reason I ask is....
Go to NAPA (or what ever the equivilant parts store there is). Your looking for a product called "Sea Foam". It's what they use to clean large marine engines with. Get 2 bottles of the stuff.
Un-cap a vac port on the intake manifold and use a tube (medical grade or vac line work well) and, with the engine running, start to dip down the tube into the can of seafoam. This will want to kill the motor, as you will notice the idle will drop. Have someone in the car to keep it going, but don't rev. Just use your hands to vary the flow of the liquid into the engine. When you've gotten about 1/2 way through the can, stick the entire tube into it, which should shut off the motor. With a funnel, slowly poor the rest of the solution down into the intake manifold.
Now for part 2.....
Remove the oil cap from the valve cover, and dump the remaining can of sea foam into the valve cover.
Le the entire car sit for about 10-15 minutes. Get in the car and crank it up... your going to billow TONS of while smoke... I mean TONS
It's all that carbon and nastyness going bye bye.
Now, with this cleaner in your oil, it's going to degrease your engine (lightly) from the inside out. You only want to run it in there for about a day maximum, of non-hard driving. After a few hours of normal use, drain the oil completely (have it "sucked" out at shop is the best way) and do a fresh fillup w/ filter.
I'm willing to bet your tappet problem will be gone
You got a nice clean engine from top to bottom. If you need to clean out the throttle bodies and the front of the manifold missed by the seafoam, get a can of "deep creep" and spray it in there while the engine is running. Note: KEEP YOUR THUMB ON THE STRAW EXTENSION! If not, it could get sucked right off and that would not be good!
If you haven't already, while your doing all these fluids, drain your trans oil and refill with MT-90 from redline synthetic. You can do the differential oil as well.. but I warn you, it STINKS.
MM