aftermarket fuel gauge wiring

[momo29]

i need help with wiring in an aftermarket fuel gauge(auto meter..etc...)
here is the problem:when i start my car the fuel gauge needle jumps to full even if it isnt full,it stays there for i little while and then drops to empty and doesnt move again. i am having to use the trip meter to determine how many miles i get to the gallon on an average of 20 mpg. i am tired of doing this and i need help plz.

[s10mods]

I am wanting to make an aftermarket gauge cluster for my GP (which I did for 2 of my older trucks) but the only gauge I am worried about is the fuel gauge, let me know if you get this figured out. I know on the older GM's the fuel gauge ran directly from the sender usually 0-90 ohms to the gauge, now it runs threw the pcm which sends a siginal (most likely 0-5Volts) to the gauge from the pcm, which makes wiring an aftermarket fuel gauge a PITA. I have seen that autometer makes a programmable fuel gauge now, but I dont know if it would work or not. it would be sweet, I already have a gauge cluster layed out already with some gauges, just need the rest including the fuel gauge.