Hello to everybody. I'm a newbie. I have a 94 Galant Super Saloon with auto transmission. When I shifted to drive/reverse mode, the revs dropped to 600-700 rpm causing engine vibration and eventual shutdown. The local mechanic replaced the servo drive assembly and cleaned the throttle assembly but still the problem exists. In idle mode the revs seem to be normal. I have to give a little gas to avoid engine shutdown.

HI
Check the intake hose between the MAF sensor and the throtle body for cracks
or a loose clamp
Some times when u go from drive to reverse, the engine moves forward and if you have that hose loose the engine idle drops rpm or rought
Sorry about my english I`m from Ecuador South America
good luck
Clubman

appreciate your concern, but i checked the intake hose for cracks or loose clamps and everything seems ok. I would like to rephrase my question to give you a clearer picture.If I am in drive(D) at a stop the RPM start to go down to about 600revs and causes engine vibration, also same thing happens when in reverse ®.But when I put it in park (P) or neutral(N) position the RPM goes back to normal.my local mechanic replaced the servo drive assy and clean the throttle assy but same problem still exist. I would appreciate very much any feedback from readers.