Hello I am an American working in Poland and have a 2001 S320. If I drive very gently without any hard acceleration or hard downshift all is fine but if I try to accelerate quickly like passing the car loses power and RPM's. OnceI lose power I have to turn off the car and restart and all is fine if I do not hard accellerate.The last time I hade it serviced the mecanic said the car had a breathiung problem and it would take some time to diagnose. (I was not having this problem at the time. It happened ~ a month later.)
Any help?

Thanks Curt

 

Curt,
Does you "Check Engine" light come ON?
Need to get engine codes read with a scanner.
Suspect engine dropping into "get you home" mode due to severe misfire.

Subject to the codes I suspect Mass Air Flow sensor but a misfire could be caused by many things.

Codes will; reduce the field somewhat.

Stuart

 

Stuart,

The check engine light is on the last service they got the light out but said the engine was not breathing right (comunication here is very difficult) They said they would need the car for a day at least to diagnose (possibly catlytic converter) the light came back about a week later. It is a very strange problem in that the loss of power fells like an engine issue but if I try to get th RPM's up the trans seems to slip and or shift eratically. I may be going into Limp mode but I am not sure. As long as I do not accellerate hard. Also once the problem arises the idle is very low and lumpy. Once I turn the ignition off and restart it is fine.

I will be taking it in as soon as I have some time away from work. I just want to try and gain some info/knowledge to help witht he language issue.

Thanks
Curt

 

Stuart,

Also I am wondering if the brething issue and this problem is related. I am 99.9% sure i need to replace the cats because I was not aware that LEADED gas was sold anywhere these days but alas it is in Poland
and it happens to be the highest Octane which I was using. I know lead ruines them but is the ruined a drivability issue or an envromental only issue?

Thanks for the quick reply's and knowledge.

Curt

 

This is a straight forward problem.

CEL (Check Engine) light advises that a fault code has been set.
The fault code (DTC) advises what has caused the CEL to be set.

To turn the light off requires the use of the same scanner as is required to read the code.
If the cause is not corrected the problem will reset the CEL even if it is turned off (reset).

Since the fault symptons clear with a restart it is likely that a component out of range on "boot up" (just like on a PC computer).

Most likely candidate is the MAF.

This is an easy DIY job but you need the code to confirm that this is the problem because it could be plugs, filters, fuel, catalyst, O2 sensors, anti knock sensor, injectors, fuel pressure regulator etc etc etc.

Stuart

 

Lead kills the O2 sensors and the cats.

The O2 sensor will cause the CEL to be set since emmissions are compromised and the readings coming from the O2 sensors will be wrong and this will be sensed by the Engine Mangement system EMS.
The dead cats won't impact driveability (unless they are blocked) but this is very unlikely.
However the car might not meet annual vehicle inspection tests if you car is subject to them. (Depends on country)

Hope this helps,
Stuart

 

Sounds like a faulty MAF sensor or a faulty Acceleration Pedal Sensor. Iv worked on a car before that had a faulty pedal sensor. It was causing it go into "limp mode". The sensor not only measures how far you press the pedal but also how fast you press it. Does this problem only happen when the gas pedal hits the kick down switch??

 

Thanks MBZTech,

Yes it only happens if kicks down

Curt

 

Looks like you found your problem.Good luck!