Mercedes A140 starting problems

[alex27]

Hi there i hope someone can help my wife's Mercedes A140 classic will start but after starting it will either cut out altogether or the revs will rise and drop till almost cutting out.This problem has been getting steadily worse and as i am not working at the moment i would like to fix this myself.I had the car serviced just before this started.I took it back to the garage but they couldn't find anything on the diagnostics.I checked the spark plugs and to my horror found Renault plugs had been fitted these are now changed but i would rather not take it back to that garage which coincidentaly is where i bought the car from in january.
Thanks in advance to any one with any ideas

[TWR]

Has the car "failed to start" before or after the service? what I am surmising, If there is a bad connection either on the Battery down to the Solenoid/starter your first turn would start the car up but if the car 's connection have been loose what you have taken out of the battery will not be charged enough to put back in. I hope you understand my Answer.

[alex27]

checked the battery and all fuses and all seems fine the car does start every time.but either cuts out or revs erratically.think it could be a sensor but really don't know thanks for your reply

[chas2008]

i think you are on the right track with a sensor/ air low meter or similiar, just need to sort out which one, was the garage that used the diagnostics a Merc dealer ? although all garages have some form of diagnostic system they never seem to be as thorough as a main dealers system which probably cost 5 x as much. Without a fault code its a bit hit n miss

http://forums.mercedesclub.org.uk/showthread.p hp?p=354697

http://www.aclassinfo.co.uk/mypage.38.htm

http://cgi.ebay.co.uk/MERCEDES-A-CLASS-AIRMASS -METER%2FECU-REPAIR_W0QQitemZ400034816466QQcmd ZViewItemQQimsxZ20090304?IMSfp=TL0903041210003 r23696

just some links which may or may not help...