The engine speed does not fall

hello

first thing, sorry for my english.

just bought a tacoma 2005 4x4 with manual transmission. I changed all suspension parts and breaks. almost ready to go

but one problem has not been solved. when Im driving and changing gears (specially 2-3 gear), the engine speed they not go down. they hang on two seconds and slowly falling down.

is this a regular things ?

any ideas, thanks