Fuel gage does not work, does not move at all when we full up or after usages stays at 1/4" tank, sometimes shoots up or down only to return to 1/4 tank. Speedometer will not work about 10% of the time, will not go below about 60MPH, seems to return on its ownafter imtermitten falure
Fuel Gage not working and speedometer works 90% of the time on 2005 GMC Envoy
by GMCA1 in Des Plaines, IL on March 30, 2011
ANSWER by Jim Taddei , March 30, 2011
It sounds like you may have two problems with your 2005 GMC Envoy. The speedometer problem is most likely internal to the cluster and the fuel gauge issue is most likely related to the fuel level sensor in the fuel tank. You could try having instrument cluster repaired first to see if that will fix the fuel gauge also but I doubt it will.