In my gpas truck you can floor it and the gas gauge will go from full to empty. The sending unit in the tank messed up.

 

+1 on what AIM said. also check the CAT

 

Just to let you know, the LAST HALF of the fuel tank (after the needle hits half tank) does not have as much volume as the first half. You can get about 175 miles on half a tank STARTING FROM FULL, but you can only get about 75-100 on the second half.

Think of your gas tank as an upside down triangle (or funnel) and the "half" is a line HORIZONTAL not vertical.

I know because when I am at 1/8 tank, I can fill the tank with 8 gallons and be a little over half full. But to fill the rest takes about another 14 gallons.

 

And to think at one point i asked so much about the plenum. With almost 150,000 miles and multiple previous owners. I must have been taken care of a while ago....I HOPE

 

ok my last tune up was 5 weeks ago and i changed the rotor button and wires and plugs and what not the cat well its brand new has a complete flow master exhaust, along with the O2's the gauge reads correctly cause when i put 20 in it twice i ran out of gas quickly lol so i went back to my nissan for a lil while haha, but i will look into that plenum how hard is it to change?

 

and also i thank each and everyone of yalls input its nice to know people care and can help thanx again

 

If you have never done it before, I would suggest giving yourself a whole day. take your time cleaning up the mating surfaces before reinstallation.

 

I would up that to a weekend. Granted I replaced a few other things and modded the keg, but it's a process that you want to take your time with. And if you snap intake bolts - a lot of potential added time there. Luckily I only snapped one.

 

ok guys great my poor gas mileage was due to my temp sensor not working at all " how is that???? " i replaced the temp sensor and well i can driver on 20 bucks for a few days now and and its back to it's old self i also had to replace the idle air, thats what the computer told me to replace then i did such and my temp gauge works again and my gas mileage is back to normal, my last question is why is that replacing these sensors have anything to do with my MPG

 

Because they control your air-to-fuel ratio