1.) Check spark plugs - This is the first thing I tell
people to do if they think they've got a problem. Pull
all your plugs out and take a look - it will be obvious
if one cylinder is having a problem.

2.) Do a leak-down test - If you think your engine is
down on horsepower a leak-down test may help you locate
the problem. It will find blown head gaskets; broken or
stuck valves; and bent or burned valves. If you're
missing a lot of power you'll need to see over 20%
leakage.

3.) Inspect oil filter - Same as your weekly
maintenance. If bearing problems are caught early by
checking the filter, you may save thousand of dollars
in repairs. A spun bearing will give little warning -
if you think there is a problem, check the filter (it
will be obvious).

4.) Check drain plug - If you're at the track and don't
have a way to inspect your filter, the next best thing
to do is check the magnetic drain plug (You do have
one, right?).

5.) Inspect valvetrain - Check the valve spring
pressure; valve lash; look for broken coils on inner or
outer springs; broken rocker arms; missing lash caps
or; broken or bent pushrods.