Optional Information

2004 Nissan primastar 2.5 140

Already Tried:
Hi,
The primastar stop, service, hand brake and abs lights starting flashing every now and again.
then they started to stay on for a while and the speedo dropped to zero. if it revved above 2500rpm engine warnig light came on.
Took it to a garage who plugged in gizmo and said faults were egr valve, air flow sensor, gearbox hotwire for speedo, abs system and suggested changing egr valve first. however they couldnt get hold of one straight away. so drove home.
on way home went over bump and all warning lights went off and speedo working and revving correctly.. now sometimes when i go over a bump the lights come back on and sometimes they dont.
i guess it is an electrical fault, but can anyone point me in the right direction?
Many thanks
Craig