So I just changed the battery on my 97 C230 and now I'm having problems with the car. After replacing the battery I let the car idle for 5 minutes. The idle was pretty rough, not like it was before I changed the battery. After five minutes I put it in drive and the car started balking. Getting the car to 2k RPM would cause it to misfire and the engine would stop until the car dropped back down in the 1k area. Any idea what could be doing this? I wasn't having this problem before. Thanks!

 

Nothing is wrong with your car. When the battery is disconnected ECU /engine management system/ lost the memory. When the engine is restarted it may idle and run roughly until ECU has 're-learned' the best settings. Take the car for a road test of at least 15 minutes duration, covering as many engine speeds and loads as possible and concentrating on the 2000 to 4000 rpm range. When you are done, let the engine idle for at least 10 minutes, turning the steering wheel occasionally and switching on high current draw equipment such as the heater fan or heated rear window. Keep in mind that ECU required battery power AT ALL TIMES. MB dealer use device 'memory saver' plugged into the cigarette lighter socket, before battery is disconnected so ECU has permanent power until the battery is replaced for new one.

 

Thank you platonmind! I did what you said and it seems to be fixed. The engine died a few times while driving up hills but after 30 or so minutes the car was working perfectly.