No more SLUGGISHNESS on 90 300TE!
FIXED IT! No more sluggishness!!!
For me, it was the fuel distributor.
I have replaced the following items; the fuel pumps, O2 sensor, fuel filter, idle control valve, eha, vacuum hoses (now, no vacuum leaks, tested with a smoker) spark plugs, plug wires, distributor cap and rotor and have performed the following services; checked fuel tank filter, cleaned injection system with high pressure (80 psi) injection cleaner machine, checked and cleaned small filter in fuel distributor.
Here was the process I performed in the following order. Replaced 1. plugs & wires 2. cap & rotor 3. cleaned injection system 4. replaced suspect vacuum boots and hoses 5. O2 sensor 6. replaced fuel filter 7. replaced idle control valve (this fixed it dying when coming to stop 8. cleaned filter at fuel distributor 9. replaced fuel pumps and checked screen in fuel tank 10. replaced eha and finally the item that fixed it, 11. replaced the fuel distributor.
Throughout this process I had a friend at a Benz repair center use their computer to set the fuel mixture (?) through the hole in the air cleaner with not much change in performance. I'm sure I've left out some minor steps as this took several months. Now the car idles smooth and everytime you press the gas, it goes. Believe me, I've tried to get it to mess up but it just goes. Although I have to admit, I keep expecting the sluggishness. I hope this helps and if you have any questions, I'll try to help.