orgazmick

Hello ok let's start i have a 1997 scooby uk turbo and ive just got it back from haveing the gearbox overhauled the gargage only took out the gearbox 2 fix a seal on the main input shaft and check it all over .that bit is/was ok but now the engine stalls at most junctions .so i connected the black connectors and read the fault code :which was --.... ie 20 4 which i think is the idle air solenoid is this correct ? and im a right in checking this connection u just pull it off and push it back on a few times 2 make shur u have a good contact or should i measure for any reastance with a auto meter and if so what reading am i l@@king for thanks guys ps is it the switch on the or near the thottle body with A B C on it thanks