First time poster, thanks for any guidance on this.

91 300E - 139K miles. On warm starts only,after sitting for 20+ minutes, any ambient temp, engine fires right up and idles like it is on 3 cylinders. Will smooth out if left alone or accelerator is pressed. Faster if accel is pressed.Classic case of fuel starvation. Fuel pumps hold pressure for 45 minutes. Check valves replaced in pumps, no change. Fuel accumulator replaced, no change. Fuel pressures holding 3bar+. Injectors cleaned and flow tested, no change. New injectors, cleaned and flow checked, no change. Fuel filter just 11K miles ago.

I'm thinking that its time to think beyond fuel and look at ignition. You need 3 things for combustion, air,fuel,spark. Ruling out fuel, look at ignition coil.?? Cap,rotor, plugs and wires were replaced in April.

Look at cap and rotor to see if they are carboned?

Cold start valve works, pressures are good and hold well.

What are some thoughts?


Plugs have about 3K miles since new and are excellent, light tan in color.

Thanks for the help