Help 3rd gear not working
 

Hi everyone just joined this forum and hope that someone can help me.
I have a 2003 volvo s60 2.5 t and recently had the flex plate ( the plate that the starte runs to or is connected tostart the motor) replaced. When i went to pick up my vehicle the mechanioc told me i have no 3rd gear (in manual or auto). After a huge argument i took my car to try and let volvo tell me why i didnt have a 3rd gear because i had one before.

So my question would be what would cause this ?
In manual i can shift from 1st to 2nd and then skip 3rd and go to 4th and 5th.
Im auto it just goes to 3rd and then doesnt shift further.

Someone mentioned that it might be " the switches" what is that?

Secondly this last week it started stuttering like it is not getting enough petrol thru. Now when it gets warmed up as little bit it doesnt want to stay idling, so i have to rev it up a little bit continuosly. So when i drive i have to go from manual 1st to 2nd and then when i slow down or stop i have to move it to auto and then neutral.

Can someone please give me some info on what could cause this.
I recently lost my job and is on disability and cant afford a diagnostics test at this moment