Mercedes Benz repair: RPM not stable, air flow sensor, mb 190e

Question
thank you for the for my Question ID=4180523 and it helped me to find the starting and high idling problem I found  air flow sensor and idle control wire plug are connected wrongly   I inter change now problem is ok  thank you for the answer


after that I have  problem in engine it I not stable in idling and on the gear
Car starts fine and after some time the   RPM  become un stable it varies from 900 to 500
I observed the economy of fuel gage comes to half  when  RPM  comes to 500  can u help me to fix the problem
Car  MB 190E 1990Y
Engine  temp 80  

Answer
Read these threads, they may help:

190E Throttle surging.
http://www.mercedesshop.com/shopforum/showthread.php3?p=1011063#post1011063

Weird idle problem involving Overvoltage Protection Relay
http://www.mercedesshop.com/shopforum/showthread.php3?p=31090#post31090