TULSA - The more you fill up, the more it adds up.
"I'm just barely halfway at $50," said driver Tim Raymond.
Tim Smiley feels the same pain at the pump.
"Our gas budget, it's went up probably $50 to $60 bucks a week," said Smiley.
In fact, for Smiley's family it could put the brakes on summer vacation.
"It kind of depends on how the gas prices go," he said.
But maybe you don't have to hold off on a road trip after all.
Working with our partners at the Scripps Howard News Service, we collected one-gallon samples of regular unleaded and premium fuel from eight national brands across three states.
We took our samples to Paragon Laboratories, an independent, certified testing facility near Detroit to find out if all brands are created equal when it comes to detergent.
"One of the worst things you can do is to go from brand to brand to brand, getting the cheapest stuff you can find," said Tony Molla, the Vice President of Communications for the National Institute of Automotive Service Excellence.
Molla says if you repeatedly fill up with gas that doesn't have enough detergent, deposits can build up causing your engine to burn more gas.
"As the deposits build up, they tend to attract more deposits so it's very much like a process that the longer it goes untreated, the worse it becomes," said Molla.
Paragon performed unwashed gum tests. The same test automakers use when spot-checking to see if gas meets their standards. Scientists boiled each sample and measured the residue left behind. The more residue, the more detergent, which could equal better gas mileage.
In our test of regular unleaded gas, Exxon had the highest level of additives, with 20 milligrams per 100 milliliters. BP and Shell followed close behind, while Marathon, Citgo, Pilot and Speedway samples each had less than half the amount of detergent found in the top three brands.
"Obviously, the more detergent, the more efficient job it's going to do of cleaning the valves," said Molla.
You pay a premium for gas that's 92 or 93 Octane, and in our test, Shell leads the pack with 31 milligrams, followed by BP and Exxon. We found the lowest levels of additives at Speedway, Mobil, Citgo, Marathon and Pilot.
Pilot's 8.8 milligrams is three times less than Shell, but in a statement, company vice president, Alan Wright, told us "Our gas blends meet EPA requirements. We don't put in extra."
Still many drivers we talked to say quality isn't their number one factor when buying gas .
"Price, first and foremost," said Raymond.
"Price mainly, with these prices it's unreal," said Smiley.
Even a few cents more didn't make it worth for them. In fact, only one said he'd be willing to pay a little bit more.
Ernest Companion does a lot of traveling for work and fun. "I would consider paying more, a little bit, a cent or two more a gallon. I look for good quality gas that's reasonably priced," said Companion.
According to our expert, he's got the right idea, as long as Companion doesn't switch around too much.
"We always recommend that you try to find one brand of gasoline that you like and stick with it or at least one location," said Molla.
So when hitting the road this summer , you might want to choose carefully which brand you fill up with because there's certainly one thing we aren't choosing, the price at the pump.
"There's not a whole lot we can do about it. We're just going to have pay it," said Companion.