throttle or gearbox or what else???

[janko39]

after a regular service I have been advised to get a gearbox checked, technician reported harsh shifts and slips. having this checked everything was found OK with a gearbox, faults found with throttle pedal. throttle pedal replaced /including TPS/, no problems with shift, car was running smoothly. after few months the problems re-occured, harsh shift, jerky shift, car jumps when shifting up/down, engine rattles during kick-down, also noticed poorer performance, higher consumption, pulsing power while running on motorway. What can cause the problems? faulty throttle pedal again??? Or is it a problem with the auto gearbox? anything to do with electronic throttle actuator /ETA/ or with ASR or ESP. any help, please??

C200 CDI, auto, 135k miles, 2004 W203

 

[jonathanc]

Faulty MAF? That may account for the poor performance and mileage, I think the gearbox also uses MAF information to calculate something or other (load?) so that may account for the poor changes. Sometimes disconnecting it helps, it is not a solution but makes the car use a default value for the MAF. If the performance improves and the gear changes are better, good chance it is the MAF. Might also be worth just checking that there isn't water leaking into the car on the throttle sensor.

 

[janko39]

hi all, any other suggestions or ideas, please??? I do really need some help with this. thanks in advance.

 

[nigel cross]

Has the auto oil been changed recently?
Has the level been checked?

 

[x332race]

Could be one of a number of things....best to get it on a "star" machine and check for fault codes.

 

[janko39]

hi all, just got home from MB dealer, left a car there for testing, hopefully it will be only the throttle pedal again and nothing more serious. but will let you know about the outcome. thanks.

 

[janko39]

nothing wrong???

hi all, just to keep you up-to-date... all checks and test results are in specs. throttle pedal tested, OK, engine fully tested, all cylinders, pressures, etc, OK, all electronics tested, ECU, etc, OK, gearbox tested, OK. softwares re-loaded. gearbox oil + filter to be changed soon, but level checked, oil quality checked, OK. but still not happy with a jerky shift and rattling engine, but i was told that is normal. any comments, ideas???