car dies after clutch install

[Leinad]

I just had a clutch installed and if i come to a stop the car will die. Not suddenly but slowly enough were i can notice and rev it up a bit. Also the clutch is VERY soft, feels like almost no pressure at all(im not liking that). Also when i start it up if i dont rev it a bit it wont strat and it will just quit, and when i rev it when i start it like that the rev surges when i'm holding it at a constant. When i drove it away from the mechanics garage he told me about it and i just figured my s-afc setting had gotten reset. Well when i checked the settings after i had gotten home they were exactly the same as they had been when the car ran fine. The mechanic said it could be a bad o2 sensor. could that be it? or what else could it be?

The car has also been sitting for about a month waiting to get fixed and i just got it back today. Could it just be a lack of use?

 

[NOMIEZVR4]

i highly doubt it can be a lack of use, i have my transmission open for about 2 weeks now cuz my act clutch hasnt come in yet, ill have taht on by a week and let u know about that but if the car wasnt doing it before and started doing it after the install, then the install was done wrong. try to take it to another mechanic

 

[Leinad]

it was doing it before the install but i just didnt realize it. I just though it wouldnt start cause of clutch problems. So i didnt give it any gas to get it started cause i was afraid i would damage something. My clutch and pressure plate were killed and i was waiting the get them in and get it fixed. When the trans was apart we found the front trans mount was broken. So until now i had thought it was just a problem that went along with that stuff. the car drives GREAT while im moving.?.?