I'm new on the forum since just purchasing a 1971 base coupe. The car is very sound and runs great but has a few little issues I'm addressing. I've been lurking around reading prior post. The wiper door on my car opens when I start the car. Then, as I'm driving around it closes and reopens intermittently. Seems to close when RPMs are UP and then opens when car goes back to idle. Anybody experienced these symptom and know the fix? Thanks, Joe

I am going with a vacuum leak.  I am unfamiliar with your year but thought I'd chime in to let you know that someone with more knowledge will answer.  Also, Welcome to the club!

Probably the vacuum regulator that is mounted on the back side of the passenger wheelwell liner.

+1 on Gary's response. You should also check the vacuum check valve. It should allow vacuum to travel from the headlights, wiper door etc. to the intake manifold, but not the other way. Look for the main vacuum hose coming out of the intake manifold behind the carb. Follow that line you should come to a small plastic disc thing in the line (vacuum filter). A little farther down the line you'll see a similar metal disc shape that splits the vacuum into two lines one goes forward up to the head lights, the other goes towards the windshield wipers and cabin. That metal disc is the vacuum check valve, make sure air flows only one way, towards the motor. If that check valve is faulty the wiper door and headlights may pop open when the engine vacuum drops. Easy to check, easy to replace if faulty. Welcome to the site and good luck !!