took the car to the shop for some services done, the mechanic told me that he saw my gas receipt from Costco, and advised me to never put in Costco gas again, said it had too many residues, your thought?

 

Find a different shop.

 

Costco is top tier gas with detergents to help keep the fuel system and combustion chamber cleaner compared to non-top tier fuels. I switch between Sam's Club and Costco depending on which line is shorter (both are usually blocks from each other in the NM).

 

I think you need a new mechanic. Acquaintances used to fill up at Costco all the time; during pizza delivery, he drove 260k in a Honda Civic without any problems

 

I use Costco gas in my '14, more than 90% of the time. I have put 45,000 miles on it since I bought it used in 2021. It has 160,000 miles on it now. Never a glitch.

I too would find a new mechanic. Anyone who operates on beliefs without evidence may do something inappropriate to your car.


RFT!!!
Dave Kelsen
--
"Look, I don't want to wax philosophic, but I will say that if you're alive you've got to flap your arms and legs, you've got to jump around a lot, for life is the very opposite of death, and therefore you must at very least think noisy and colorfully, or you're not alive." -- Mel Brooks

 

If your mechanic pulls this BS fast one on you, I wonder what else did he do that you’ve never found. Find new mechanic.

 

+5 on find a new mechanic... that guy is smoking the good good

 

For sure lmao. Costco gas is considered one of the best to grab.

 

I have been using Costco gas for at least 15 years with no issues whatsoever. The only thing I don't like about it is the mix of Methanol in it but I guess that keeps the price lower.

 

Another vote for a new mech. Continue using Top Tier gas and don't worry about it. Much better than a no name gas station that barely sees anyone. That's one thing about Costco, you know they are constantly getting new gas as it's always busy. It's either Shell (due to the CAA discount) or Costco for both of our vehicles.

 

I used to hear this sentiment a lot too that Costco gas is bad, but Costco is such a reputable company that consistently offers quality offerings, no way in hell is their gas bad. The skeptic in me thinks it was an orchestrated campaign by existing gas stations that were threatened by Costco entering the market.