Car stalling

Speedo fault could be speed sensor which is built into you n/s/f wheel bearing .Could also check wiring .For the stalling clean or replace idle control valve .

I had the same stalling problem at junctions etc, after spending a fortune at vauxhall which still didnt cure it i found the answer on another forum and fixed it myself for less than £10.00.

there is two solutions first they suffer with real bad carbon build up remoce the big black air box on top of throttle body the one from air box you will prob find this is all gummed up spray lots of carb cleaner in and around it to clean it all up while holding the throttle half open till its all clean.

secondly the mass air sensors sometimes get a earth fault which the on board computer does not pick up, strip back the sleeving on the 4 pin connection find the yellow wire out the four this is the earth strip a small part of the yellow sleeve back solder a new bit of cable to this place a ring terminal on the other end and connect to the earth point on alternator i done both and had at least ten thousand miles of trouble free driving.

before i done the above i spent over a grand at vauxhall on new ecu then software upgrade plus throttle posistion sensor plus labour hope this helps you and others