I have scoured the forums about this as well as picked the brain of many a mechanic from the experienced DIY guy to professional garage business owners and the consensus ranges from these products doing basically zero to them being extremely helpful and effective. AS far as the C5 corvette goes specifically, what do think about these products? From the one every 3000 mile fuel treatment to thee every fill up kind to the oil treatment, to transmission treatments to the $20 total full system cleaners? I have a 93 and an 02 corvette and I routinely add some chevron fuel treatment to the tanks around oil change intervals and before a long trip of highway miles I will sometimes add some STP treatment that is instructed to be used every fill up. They are pretty cheap to be honest and I don't use them enough to really be "wasteful." (unless of course you guys change my mind to them being totally useless!) The only ones I have ever used are fuel treatments and while I have not seem any drastic changes/improvements in my cars performance or efficiency, I have had zero engine issues from any of my 3 older and high mileage cars at all and no deterioration of performance/efficiency as they have aged. I am ALL about preventative maintenance and preservation as I LOVE my corvettes, esp my C5, and I want to be happily driving it until 300k mark with as little issues and repairs as possible along the way.

 

If you use quality gas (known as Top Tier gas) sold at Shell, BP, others, you don't need to add other stuff. They already come with the stuff to keep your fuel system running optimally.

 

shell stations are pretty much like a needle in hay stack here. I use BP

 

I've been participating in the CF website since 2001. And from that time to the present, the additive Techron, has been recommended to keep the fuel gauge working properly.

 

Keep your gas tanks full and you will not be pulling deposits from dirty gas off the bottom of your tank. Running on empty is not a good thing to do. As far as chemicals if it makes you feel good use them.

 

Retail fuels have a 90 day stabilizer in them. Old gas and running the tank low are the primary concerns for a vette guy/gal.

When storing for longer than 2 months I use sta-bil and fill it up.

For regular maintenance I use a little acetone which will help injectors and atomize the spray pattern better.
Maybe once a yr I use techron additive. (less than 3k miles per yr on my vette)

 

IIRC, the owner's manual says not to use additives - especially engine oil additives. Top tier gasoline (major brands plus Costco for one) is good enough. If you run on "noname" or supermarket gas, Techron is the best of the additives to make up for what the cheap gas may not have in its additives package - all manufacturers use the same "base" gasoline, the wholesalers add the appropriate brand package depending on who they are delivering to.

The gas gauge-to-zero issue was essentially a software problem, where the system did not recover from a fault. Fixed way back when with an ECU update (reflash). I have an early build '98, used to do it all the time. Not one instance since the reflash many years ago.

 

I’ve used the 104 stuff when getting 91 from Costco ! It works !

 

I use predominately BP gas 90% of the time. There are kangaroos and BPs everywhere here. There is one exxon and Mobile 1 station not too far from where i work too. Only shell i know if is too far oit of way to even consider. Is BP as good as exxon and mobile 1?
i have never used an oil additive even tho mechanics have said on occassion it was good idea. Only fuel additives few and far between.

 

Costco gas for my application haha haha I tried it once never again ! The 91 my engine was knocking like the police was at the door lol ! After some 104 additive all knock gone and never returned their with my vette stay away ! I usually got to chevron or shell it’s more expensive but you get what you pay for !

 

haha i dont blame you. Gotta stay away from that dirty el cheapo gas. Im shocked at a few people i know that actually use 87 in their vettes and lots of times from the cheapest station they can find. Ive heard somewhat car savvy half mechanic people say this was okay and politely said okay but never asked them another car question again because of how ridiculous that was. Even in my e38 that runs okay on 87 but 91 is reccomended i always use 93. Only options here in nc are 87,89, and 93. Had to fill up on 87 twice around hurricane gas shortages but besides that ots 93 all the way. Why use lower grade just because technically the car "CAN?"