1981 VW Rabbit hard to start when hot?
Could be bad compression, with a bad head this problem gets
worse with higher temperatures. Hard starting at hot could be a
failing ignition coil, does the engine miss under load at hot? It
could also be a failed fuel pressure accumulator or fuel check
valve. Scrooch under car, find the fuel accumulator ahead of rear
wheels on passenger side. Next to the fuel pump (the noisy unit
humming along during operation) there is a can with 2 lines going
into it. It's smaller than a soup can. If the car has high miles I
would just replace the accumulator as it will probably have failed
in the 28year old car. If replacing the accumulator doesn't help,
replace the check valve on the fuel pump.