when i press on the throttle sometimes it feel liks there is a small resistance, like it's "sticking" to something.

also another thing when i pull hard on first gear the transition from 1st to 2nd is hard because it seems that it won't let go of first gear.

???????

 

check the cable and also the ring around the throttle plate, sometimes some carbon buildup will cause a sticky throttle when mostly closed. also check to make sure your throttle cable is mounted properly and isn't getting hung up on anything.

 

does it idle werid? when you release the gas, does it stay in a rpm? or is the throttle slowly going down? any of these, its your throttle cable. make sure its not to loose but not to tight and make sure its not clig to something. thats about it

 

it may be your throttle body. take some air intake cleaner spray and spray some inside the throttle body.

good luck