With the compressor running and the engine speed up to 1500 RPM or so, the pressure dropped to about 25 psi. I did add almost 13oz of R134a to the system. The AC system seemed to perform better, the compressor ran a lot longer (almost continuously) and the air temperature was cooler. I started to see some condensate dripping, so that is a good sign.

When the compressor cycled off, the engine RPM increased by about
400 RPM. Is that excessive?

If the system is low on R134a, can the pressure still be at the expected level or will it be low?
Likewise, if there is too much R134a in the system, will the pressure register too high?

Thanks for the help!

__________________
1992 400E (W124) - 177K Miles - fun car!!