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OTC fuel worth the mony?

While I was in the auto parts store the other day grabbing some oil I was looking at all the fuel cleaners, additives, injector cleaners and such. There were a ton of companies that offer items, they range in prices from just a few dollars up to I saw some at $20 +. My basic question is do any of these work to what degree if they do and if not then what keeps them on the shelves?

They do work for minor issues. They won’t fix a failing engine but they can clean a neglected one.

They stay on the shelves because people buy them, usually, to try to fix cars with major problems. And why not? $15 to TRY and fix some issue that will actually cost $500 to fix seems like a good bet. They generally don’t hurt anything. Sort of like buying a lottery ticket.


Some work. Some are snake oil. Some can actually cause harm. Best advice is to post here when you’re thinking of buying one, and why you’re thinking of buying it, and someone will tell you if it’s worthwhile or a scam.

Yes, most work to one degree or another.
Do you need them? Depends on the quality of the gas you use. All gasoline Is supposed to meet minimum standards for detergent additives. But many responders to cartalk only use gas certified by TopTier, these brands contain a higher level of detergents that keep your fuel system clean.
I do use an additive for my lawnmower and outboard, for these I use non-alcohol gas. The detergent level of NA gas is unknown.
So I agree with the two above comments.

I’ve used Techron on a '95 Suburban that had some pinging from carbon buildup, seemed to help. If I had a car with minor fuel issues, I’d use it again.

I just bought my first one and put it in this morning. I purchased the Cheveron Tech engine clean 12oz bottle. I put it in this morning as I will filling the car, which ended up being about 13 gallons (I believe my car is a 16 gallon tank). I have a 2011 Cadillac CTS 4 3.0 engine with around 86,000. Overall the engine runs very well getting the recommended 20+ miles per gallon in the city. It has a slight “idling” issue that I have talked about a few times on this website.

I think the right gas additives are okay if used seldomly to maintain cleanliness, but why would anybody use them constantly doesn’t make sense, unless it is last ditch efforts. Oil, transmission, stopleaks and any other fluid additives to me are a very big mistake. If it’s broken, fix it. If it’s not worth fixing, then add all the junk you want just maybe it will prolong the inevitable.

I used Marvel Mystery Oil in the gas after having some preignition pinging on my high mileage 1984 Chevy Cavalier. The ping went away and I just kept using the MMO: 4 oz. per 10 gallons as I recall. Somewhere around 190,000 miles I had the head off at a machine shop and they commented on how clean and free of deposits it was. Was the MMO a factor? I don’t know. I wasn’t super vigilant about oil changes, but probably stuck pretty close to the carmaker’s recommendations on that.

MMO is supposed to help clear out carbon deposits. I think it did, and I believe that stopped the preignition pinging.