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The issues I am experiencing are associated with my 1991 300 TE–24V M104 engine.

Operate the car to raise its temperature, without necessarily reaching 80 degrees Celsius, sometimes with a drive as little as 15 minutes.
It is crucial to allow the vehicle to remain idle for a duration of 30 minutes to 1 hour. Restarting the automobile soon might potentially cause problems.
Following a restart, the automobile sometimes experiences misfiring, however it is not a consistent occurrence.
Occasionally, instantly turning off the automobile and then restarting it would restore it to its regular state.
At times, the automobile may have difficulties starting, or it may continue to misfire, resulting in a lack of power, low idle rpm, and rough running. (At times, I would need to restart more than 20 times and the misfiring issue would persist. I would then have to wait for an extended period of time before it returns to normal.)

Modifications made to the automobile since my ownership:

8 spark plugs of the exact Bosch brand, specifically designed without resistance.
One of the two gasoline pumps (since the other is functioning normally)
Fuel accumulator
Bosch idle control valve
Aerodynamic circulation A potentiometer is a type of variable resistor that can be adjusted to control the flow of electric current in a circuit.
The distributor cap and rotor, both manufactured by Bosch.
Bosch ignition coil Camshaft position sensor Electronic control unit (ECU) replaced with a different pre-owned unit
The OVP relay has been replaced with another previously used device.
The MAS Relay has been exchanged to a different previously used device.
The cable for the crankshaft position sensor has been replaced with a different cable from a previously used unit.
The HT leads seem to be brand new, specifically Beru brand.

Could someone provide assistance in directing me to more sources? I have visited many technicians in an attempt to address the misfire problem, but they have had difficulties in reproducing the issue. This is because the problem often resolves itself just by restarting the vehicle.

These automobiles are well-known for experiencing condensation in the distributor body, particularly in humid weather. When the engine is cold, any moisture present in the distributor body evaporates due to the heat generated by the engine. This moisture then moves into the cap region, leading to high tension (HT) shorting across the inside surface of the cap. To resolve this issue, you may use a hair dryer to thoroughly dry the inside of the distributor's metal body.

I have just replaced the distributor cap and rotor using Bosch components. Are there any other measures I may take to alleviate this moisture problem?

The ECU was replaced with another pre-owned one.

Is ECU equivalent to EZL?

Indeed, the ECU has been altered, namely the one located in close proximity to the battery, not the EZL ignition control module. I have not made any changes to it.

I find it improbable. In my experience, things either function well or fail completely. However, it is advisable to get an additional one since they are becoming more scarce.

As previously mentioned in two earlier instances, I had a similar issue where the injectors were leaking gasoline when the engine was warm and idle for thirty minutes. During the first phase, the engine would experience misfiring for a period of time before resolving the issue. After completing a morning's labour, I installed new injectors, guides, and seals, and performed the usual maintenance service. Expensive but gratifying.

Regarding HT, these engines need the utmost quality. In 2020, I upgraded the complete high-tension (HT) system by replacing all components, including the coil, plugs, and leads, with genuine parts from MB. Currently, my level of confidence surpasses any I have had in years.

Prior to the refurbishment, I had a 9-month-old Bosch distributor cap (installed by unskilled individuals in Toulouse) that exhibited fissures around the central electrode, however it remained functional. The outcome was in favour of the new Bosch MB model, which, even after 2 years, still seems to be in pristine condition.

Is there a significant disparity between Bosch MB and Bosch aftermarket? They have a resemblance while in a new state.

If the shield beneath the rotor arm is old, it is advisable to replace it to ensure it is in excellent condition.

Happy hunting.

Frequently, this statement is made and I do not have any objections. However, I have never seen that issue despite the fact that the vehicle is consistently exposed to outside conditions 24/7, ranging from -5 to 40+ degrees Celsius, and experiences significant amounts of rainfall and fog.

Consistently experiencing immediate cold starts, unless I have damaged the EZL.

I presume the answer is negative. I believe he is referring to the KE controller.

I would search in the location mentioned above. The release of pressure from leaky injectors may lead to the formation of fuel vapour, which negatively affects the ability to start the engine while it is hot. Particularly pronounced in regions with higher temperatures.

The duration of daylight in your location is rather lengthy.