Volvo Repair: Engine Temp & Fuel Gauges, volvo 740 turbo wagon, fuel gauge

Question
1990 Volvo 740 Turbo Wagon.. Temp & Fuel Gauges on instrument panel only work part of the time, and not necessarily at the same exact time.. Sometimes one will work, or both will work, or one might work and the other dosen't.. Temp gauge is more prone and more frequent to malfuction than the fuel gauge.. Temp gauge usually works right after getting in car, starting it up and bringing engine temp up to normal; Then temp gauge needle starts "wiggling" from it's normal heat position back to where it reads at cold; It does this for a few seconds, then just drops to the cold spot on the indicator and stays there.. Fuel gauge is a little different acting; Sometimes it never moves off empty at start-up; It just doesn't move at all, like it has no power, and it won't come up at all during that drive period; Then after a peroid of time has passed, with the key switch turned off; you might go back, turn your key switch on and the fuel gauge acts normally, and will continue to work properly through this next driving period.. Fuel gauge either works, or doesn't work at start-up.. Any ideas on where to look for answers?? Thanks  

Answer
Mike, Since the thing is wiggling, I suggest replacing the sender in the cylinder head.  As far as the fuel gauge goes, you can do 2 things.  Remove the cluster and tighten all the connection screws or you can just tap the glass and the gauge will work.  This is a common issue with the 740's. Same goes for the temp gauge but the sender will help it some.  Roger