How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Matt Your Own Question
Matt
Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 21876
Experience:  BEng hons Mech engineering, in auto industry 22 years
12772297
Type Your Mercedes Question Here...
Matt is online now

I have a 2002 slk 3.2.About every 6/700 miles the car will

Resolved Question:

I have a 2002 slk 3.2.About every 6/700 miles the car will stop running evenly and engine management light will come on.Clears itself after a couple of days.Been to two merc agents and had plugs changed due to management system saying cylinder i gone into limp mode.If car is not used fauly clears quicker.New cat some spark plugs,ignition coils and cables changed.Worried it will become like triggers broom and we will slowly replace the whole engine.
Submitted: 3 years ago.
Category: Mercedes
Expert:  Matt replied 3 years ago.
Hello

This sounds like an electrical actuator or sensor at fault .Usually when you can cycle the ignition key on / off and then restart the engine and the fault is gone temporarily this indicates that this is an electrical component causing this issue.

This could be a wiring issue as things tend to expand when hot and its possible a poor or partial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;
Airflow meter
Crank position sensor
Cam position sensor
O2 sensor
Throttle position sensor


Also worth checking the connections to the fuel pump for the same reason - unplug each in turn and give them a good squirt of switch / contact cleaner - Not WD40

and also unplug and inspect the main power relays and fuses for signs of overheating or corroded terminals - so the ones for the ECU and the fuel pump

And also unplug the wiring loom connections in the engine bay one at time and inspect for corroded or recessed pins.
Matt and other Mercedes Specialists are ready to help you