Inst. Cluster issues

So recently I've replaced my Alternator, and battery. I just got a full tank of gas. and the gas gauge only reads just over three quarters of a tank, and im 100% sure i got a complete full tank of gas, and i dont think any of the other gauges are reading right, but i cant be sure of that. I dont know if the sending unit is to blame or if anything else is messed up. any info would be great

P.S. I drive a 1993 Olds Cutlass Supreme SL with the 3.1L V6, and its the analog Inst. Cluster. NOT DIGITAL

what guages does your cluster have, and why cant you tell if they arent accurate?

i have the Oil pressure, Collant Temp, Mph, RPM, Voltage, and gas, and well the voltage always reads below 13, like 12.5 or something. and my multi-meter reads 13.8. so im sure that gauge isnt right. the gas gauge only went up to 3 quarters after i got a full tank, oil pressure i could have sworn used to read a little bit higher, but i cant be 100% sure. and the coolant temp just always moves around, but it never peaks really high so i dont worry about that.

sounds like the float in the tank is binding up. Common problem for the W-bodies.

I don't know about your cluster, but the 1992 cluster in my 1988 is VERY accurate. You could have a cluster problem, but I don't know how to go about testing for a faulty cluster at this time.

I would keep an eye on the guage and see if it goes down at all. If it does go down, then it sounds like your float is binding and not going all the way up. If it does not move at all, then it is stuck.

Either way, you have to drop the gas tank to fix it, so you might want to go ahead and invest in a new pump, strainer, and pulsator while you are there.

i found the problem, a spider got in, and made webs that i couldnt see over the gauges, took it all apart, cleaned it out, vaccuum and such, all is good now, everything works, even better then before. so no worries