560SEC 1989 tends to turn off but won't
 

On my 560SEC 1989 recently it tends to turn off but won't. I did the followings:

1. Checked the 8 spark plugs and all are good.
2. Changed the 8 spark plugs wires with original Buro ones.
3. Cleaned the rotor and its cap.
4. Changed the coil with original Bosch one.
5. Aligned the fuel distributor properly.
6. Checked the idle module and idle valve.

After all I still have the car on idle sometimes tends to self-stop the engine be it doesn't, any idea why? Thanks : ))..

Check your Idle Module. One these cars the idle can go crazy and either be really high at idle at times and really low at times or a combo of both. When your car is at full operating temp, what is the RPM's

Sorry I forgot to type that I checked them as well. (I edited my post)
The RPM is so normal arround 8. But I noticed that on cold on the morning when I switch on the engine (with no problems) I noticed that the RPM goes for 8 only even when the car is so cold while as it was and should be on 1.2 RPM for a few seconds.

I changed the fuel relay and going to test it today.

I changed the fuel pump relay but the same problem:confused:

What else I should try?

Now sometimes it turns off. I guess it's an air leakage somewhere, Anyone agree?

"recently it tends to turn off but won't"

I'm pretty decent with cars, but sometimes the language illudes me. Can you expand on what the above statement means? Are you stating the car won't shut off or are you stating the car is dieing (stalling)?

Can you describe the event as to what happens, including such info as when it happens (cold/warm, in gear/out of gear), how often, whether only at idle, or driving down the road?

ok, regardless of the car temp. hot/cold the RPM on idle goes too low (arround 4 or less) so the car tends to stall but suddenly the RPM goes high (arround 1.5). While driving sometimes I feel that it's doing the same thing regardless of the speed.