'04 Chevy Avalanche fuel gauge and shifter gauge PRND321 not working and temp gauge needle facing down ???

SOURCE: temp gauge and gas gauge not working

I had the same problem with my 2001 Pontiac Montana and the intake manifold gasket. This is a major problem with these 3.4L engines, if you are in the states I'm pretty sure there is a class action law suite against GM for this. I had my manifold gasket replaced and it was about $1000 CAD. You need to get your vehicle looked at right away as this could cause major engine damage, coolant will leak into the engine and soon enough you will be replacing that too. Good Luck

SOURCE: 2002 Avalanche gas gauge problems

Gm has a real problem with fuel tank sending units. That is what is wrong. You need a fuel tank sending unit. You can only get them aftermarket with the whole fuel pump module, but you can buy them seperate if you buy it from the dealer.

SOURCE: 2001 chevy silverado 4.8 gas gauge not working properly

Fairly common problem with GM vehicles. The sending unit in your tank has a small circuit board that an arm is attached to which moves up and down according to your fuel level. This circuit board and arm are not making good contact. Unfortunately the only good solution is to replace this part.

Testimonial: "thought probably that was it but better off replacing whole unit .i was for for gauge proplem thanks. "

SOURCE: The gas gauge on my 2002 chevy venture is not

Hi:
Your tank sending unit is bad. Unfortunately, it is part of the fuel pump assembly, and the part costs around $400, give or take. plus installation labor. It is an all too common problem on GM vehicles, as I have had to change it on my last 2 GMs. If you do an internet search you will find plenty of others in the same boat!

SOURCE: Fuel gauge/temp gauge not working

There are two sensors, one for ECU temp. readings with two pin connector and other one with only one wire, which has been probably disconnected when you replaced the CPC solenoid - very close position.