When my 2002 envoy gas needle gets to 1/2 a tank it seems to drop to E twice as fast as it did to get to 1/2 from full without as much driving. Is there anything I can do about this?

I'm a HUGE GM guy but, their gas gauge sending units are junk. That's probably what's wrong with your Envoy. It's either that or your dash cluster (gauge) is bad

both answers are good ones, and i agree, mite be the gauge,or a tapered tank,but the first thing i would check out the float in the gas tank, it's easier to get to on a lot of sedans, because you can open the tank up from under the back set assm.,but if you can get it out, there is a adjustment on the float, by taking the hole fuel pump assm. out....hope this helps

You can't access the fuel pump from above the tank on any Envoy. You have to drop the tank. GM floats are not adjustable.

"You can buy GM adjustable sending units all day long on ebay' GM Fuel level sender, Universal 6”- 24” adjustable, 0-90 ohms $22.00 Buy It Now Free Shipping

Ahhh, ok you got me there. Well, I would never put a universal sending unit in any car. I tend to use quality parts from A/C Delco and NAPA when it comes to electrical parts. I learned a long time ago you get what you pay for when it comes to electronics. Especially one that is such a pain to change because I don't want to be doing it again in 6 months.

I agree, if i was to do it myself, witch i have always worked on my own cars, since i was 15 years old, never have had any work done outside my own garage, for all that trouble of dropping the tank, i would buy the genuine GM parts myself....it is the sending unit for sure......hope this helps