Vintage Cars: 1983 500sl(euro) hesitation upon warm up, fuel pressure gauge, airflow sensor

Question
Recently replaced the following items on car, warm up regulator, idle control valve, boots and seals to the fuel injectors, plugs, and ignition control module. The car is in excellent condition and is a one family car since new. The problem is that the car recently blew a ICM and I replaced it. Prior to that the car was having some hesitation during warm up and a slight clicking noise could be heard from the glove box that was in conjunction with the hesitation. Once the car warms up it runs perfectly and the clicking sound is only heard seldomly. Could it be a OVP fuse or unit itself? Fuel pressure gauge varies upon warm up, but holds steady once warm. Also, could the clicking sound from the dash be the Vacuum Switchover Valve to the climate control and have nothing to do with the hesitation. My main concern is that I blew the ignition control module, which is most cases is the result of a current spike. I checked all the wires from the coil and the distributor and everthing looks good. No shorts, corrosion, proper grounds, and all the resistance is good in the primary wiring. The car is nearly running perfect, with the exception of this one problem.

Your thoughts

Answer
behind that glove box is a series of vacuum modules and switchover valves, 6 or 7 if I recall correctly, I would guess the click is one of those.  You could probably remove glove box insert and look more closely . I doubt a link to the stumble . The stumble on acceleration is probably a sticking or binding airflow sensor or a sticking control plunger.  The timing could be a culprit as well as system or warm control pressure ( which limits control plunger) Improper control pressures will cause a lean running engine which will stumble on acceleration.
Make sure your timing is correct, that is where I would start