This was very likely a ripoff of the Lovebug, but this VW beetle was filled with gadgets. I found several on Youtube (the Superbug collection), but I can’t find the one that I remember. There were two scenes that I remember rather vividly.

At one point, he runs out of gas. He goes to the trunk (in the front!) and retrieves a rotating key that he plugs in the engine (in the back). He rotates the key and that seems to power the car for a while.
At another point, the car has extending wheels (he goes above other cars, can climb walls in a narrow alley, etc.).

Which movie is that? I am not certain it is part of the Superbug collection. Very likely, but I am not sure.