I think I am having trouble with my rebuilt alternator...
 

The car stumbles and almost stalls when stopped at a light.

I had this very same problem before. It also has happened to me when I am on the highway and need to suddenly get off of the accelerator pedal.

Once you get back on the accelerator, car almost stalls, picks up speed very slowly. Sometimes it just "wakes up" and is off and away again.

The coughing and stumbling idling are happening at the same time of year again too, I am coming up to almost 1 year with this rebuilt alternator. It is a geniune factory rebuild.

Does anyone know if MB has a warranty on rebuilt alternator's?

Please offer anything you can guys.

Thank you very much.

Mike McKinney

An alternator problem?
 

This does not sound to me like an alternator problem.

The usual alternator problem is a failure to charge, followed by the starter turning over too slowly and then not starting at all.

This sounds to me like a bad spark plug wire problem (dampness and cold could affect a with a crack in the insulation) or a fuel delivery problem.

Perhaps by some mystical system the alternator is affecting the computer somehow, but this sounds like a lack of spark or a lack of fuel problem.

To find an arcing sparkplug wire, start the car at night in the dark and look for sparks along the wires. Rev the car up (watch out for that fan and don't touch a wire with an ungloved hand).

One easy fix might be to replace the fuel filter. They are cheap and pretty easily changed.

If your car is a Diesel, pay no heed to the sparkplug wires: Diesels are spark-free since 1892. No plugs, no wires, ignition is handled by compression alone once the glowplugs have done their part.

I am not a professional mechanic, but this sort of problem I have fixed myself before with new wires and/or a new filter.

Richard:
 

Thank you for your reply.

I have replaced the rotor and cap and wires 1 year ago. I did the alternator shortly after that. It is a geniune MB rebuild but, am not sure as to the life of these.

I am still thinking the alternator due to the similarity of the symptoms of before.

Does the rebuilt alternator have any kind of warranty? I would like to know what I should do in approaching the dealership with this one.

Please advise if you can anyone.

Mike McKinney