Using a 5-gallon scientific test measure, the CALL7 Investigators visited a number of stations in the Denver area to make sure you are getting what you pay for at the pump.

It's similar to a test 7NEWS did two years ago this month, when gas was approaching $3 a gallon.

The scientific test measure is a canister that measures liquids by the cubic inch. Five gallons of gasoline is 1155 cubic inches. State regulations allow pumps to be off by 6 cubic inches, plus or minus, which amounts to a few ounces for every five gallons.

Anything more than that, and the pump is out of compliance.

If state investigators discover a pump out of compliance, it is shut down until adequate repairs are made.

It's important to note that in all the years of testing, Colorado Division of Oil and Public Safety inspectors have not found any pumps which were intentionally set out of compliance to steal from the customer. Meters on gas pumps have a seal which, if intentionally broken, would verify to state inspectors that tampering occurred. OPS inspectors told 7NEWS, they have never found such tampering in Colorado.

When a pump falls out of compliance, it is typically the result of internal components wearing out and more often than not, when those components wear out, customers get more gas, not less.

In 2006, 7NEWS tested 20 stations in the Denver area and found three pumps out of compliance.

State inspectors verified 7NEWS' findings.

One shorted customers 8.5 cubic inches for every five gallons, or at 2006 prices, about 86 cents for a 20-gallon fill-up.

The other two stations gave customers more than 5-gallons.

In May, 2008 the CALL7 Investigators again tested those three stations, and the same pumps, and found all three in compliance.

We also tested five other stations at random and found all but one giving customers more gas than they paid for.

The only station to come up short did so by a few ounces and within the accepted limits.

Here are the eight stations we tested and the results:

Bradley at Holly & Evans, Pump #7 - 1.5 cubic inches over

Sinclair at 490 W. Hampden, Pump #1 - 3 cubic inches over

Valero at 4635 E. 74th Ave., Pump #2 - .5 cubic inches over

Bradley at 2160 S. Havana, Pump #12 - 3 cubic inches over

Conoco-Phillips at 724 S. University, Pump #2 - 1.5 cubic inches under

Sapp Bros. Sinclair at I-70 & Quebec, Pump #6 - 2.5 cubic inches over

Western Convenience at 7603 W. 13th Ave., Pump #7 - 1 cubic inch over

King Soopers at Sheridan & Hampden, Pump #1 - 1 cubic inch over

If you suspect a gasoline or diesel pump is out of compliance or have any other issues or complaints about fuel stations, contact the Colorado Division of Oil and Public Safety at 303-866-4967.