you have not suitably intimidated your neighbors in the past, thus they believe they can now intimidate you through cowardly acts.
Apparently, you are not "the neighborhood crazy guy" or "that insane lunatic across the street" or even "the weird hippie guy." You are also Not "the guy with all the guns" or even "that crazy former special forces dude." Optimally, you should at least be "the guy with the dogs who sics them on the Jehovah's. "
there is still hope for you though. You could become "the guy whos loosing his mind " fairly easily.
step one: allow your neighbors you "accidentally" see you with what they perceive as a large riffle. It doesn't actually have to be a large riffle, they just need to think it is, when you know they see you, make like your hiding it and don't want them to see you.
step two: at least twice a week, when you know said neighbor is with in hearing distance, yell and scream profanity, it is preferred to do this when the neighbor knows you are alone. do not yell at the neighbor or about the neighbor, just yell so he can hear you, at some invisible entity (yelling about aliens or ghosts can be particularly effective.) then when you know you have his attention, stop yelling, open the door and smile in his direction, a bit of froth from the mouth will add to the effect. repeat as necessary.
step three: leave the house at the same time as your neighbor, say hello politely then give him a very worried look and ask him if hes seen your dog (this is particularly effective if you do not have a dog) mutter something about hoping that he hasnt bitten anyone today for extra effect, then wonder off without saying goodbye, calling for said invisible dog.
step four: Dig a large hole in a place in your yard, where the neighbor can see. then fill it in, do this at night, during a full moon, mutter things like "i didn't mean too" and "you should have been nicer to me" while doing so. being seen pulling a large, plastic bag that appears to be very heavy and dumping it in the hole, can be particularly effective.
following the above step should pretty much prevent your neighbor from meddling with your vehicular activities in the future. Be prepared for a visit from the local constable as well, the hole in the yard should generate that visit if done correctly. However, since you have not violated any laws by digging the hole and filling it in in the middle of the night , it should not result in incarceration so long as you are "normal" to the police when they stop by, haven't actually buried a body, and don't have an illegal arsenal of weapons. if you do you may want to skip the final step.
if after all this your neighbor does not run when he sees you, you must move, however, these steps are generally effective and may even get the neighbor to move. Good luck, and may the appearance of mental instability be with you.
the writer takes no responsibility for any thing, if you end up in the nut house for factually following said advise, you probably deserve to be there.. 
