Why does my fuel level indicator sometimes not show the right level (sticks)?

What is your question?

Sometimes my gas gauge will not accurately report my level of fuel. After a while, it will again, report the correct amount of gas again. I know that sometimes in old cars, the float might stick in the fuel tank...that's not too big of a problem for me, but my real question is: Can this cause my check engine light to come on and stay on? I have had a lot of problems getting my inspection sticker renewed because my "engine light" STAYS on. It has been rejected and had to be re-inspected last year and again this year...my car is too old to have $1000.00 worth of repairs put on it just to get this "check engine light" signal to go out! Honestly, after this (3rd) year of doing this [WITH NO PROBLEM AT ALL DRIVING MY CAR] I thought it might have something to do with my gas gauge...my fuel cap is working fine, so I don't know why the float sticks...any ideas about this? (I know about the fuel efficiency and air flow indicators, but this car is just very old and runs too good to junk it!)

What makes this problem better or worse?

The only problem is this engine light won't stay off...the car runs fine!

How long has your 2005 Kia Sedona had this problem?

this will be my third year...I am not going to put $1000 worth of repairs on this old car!