Any K-Jet experts? Starting issue needs diagnosis!

[Vakito]

Hi all, I own a 1988 240 Saloon with the 2.0L K-Jetronic engine.

Once started the engine runs perfectly, pulls a strong 20"Hg vacuum at 1000rpm idle and eats up thousands upon thousands of miles without a care in the world. However all my time owning it I have had troubles starting it and to make things worse this is an intermittent fault. This really puts a lot of stress on my recently replaced engine mounts. Here's what I've observed:

- When starting the engine feels like it's firing on 3 and sometimes 2 cylinders, the throttle feels slightly more delayed and you have to rev it to about ~1500rpm for a few seconds before everything smooths out
- Sometimes it will start and immediately stall, sometimes it will start and run down over a few seconds until it stalls.
- It it stalls, the engine takes a bit of cranking to get it going again, unless you anticipate this quick enough and turn the key back to zero before it stalls, in which case it will very often surprisingly start back up immediately with no issues.
- This whole starting issue affects probably 20% of cold starts and 90% of warm/hot starts.
- I have not noticed any correlation between this problem and weather conditions
- Once started like I said, engine runs perfectly with no issues whatsoever.

Here's what I have currently done, with no success in curing the problem.

- New plugs, leads, distributor cap and fixed type rotor arm.
- New fuel pump relay
- New fuel filter
- Thorough cleaning of fuel injectors with new O-rings
- Cleaned throttle body
- Polishing of distributor and rotor arm contacts every few thousand miles
- Replacement of all cracked vacuum lines

I believe the problem may lie with either the fuel accumulator, the one way valve on the fuel pump, the ignition coil or god forbid the K-Jet metering unit but before I go throwing more money at the problem has anybody else had this experience and any success in curing it?

Thanks