In the beginning of the episode, Tim and Al are wearing tan and orange jumpsuits, respectively. But when they get "shrink-rayed" down, suddenly Tim's suit is orange and Al's suit is red.
When Tim and Al are "shrunk" and in the engine, Tim claims that the engine is a Chevy 350 small block. The engine is in Tim's Ford Mustang, which means it's a Ford small block, most likely a 289 or 302 (though with Tim's track record of a Chevy engine in his Ford hot rod, it may be accurate.)
When the kids are in Wilsons yard at the beginning with "tool man" and Tim asks what they are doing and they say nothing, you can see the fence between the yard bounce and move as the boys hold on to it. A real fence would be sturdy and wouldn't move like that.
When the Blue Angels jet with Tim in it is seen taxiing; desert and mountains can be seen in the background. Since the Taylor's live in Michigan this is the wrong background for any of Air Force bases there. All of Michigan's Air Force bases have trees near them and most on near large bodies of water. None of those things are around the base shown.