I use Marvel Mystery oil each fill up for its upper cylinder lubrication properties and its slight clean up properties. I observe slightly better mileage using it and looking down my spark plug tube holes I think its worth it because I saw no traces of carbon on them at all. But at the end it comes to preference. Some people only use it when they are trying to clear up throttle response and for that I like Berryman's b12 fuel injector cleaner for the gas tank. I only get Seafoam when I want to shoot it through the brake booster hose since it is so expensive. Your going to get a lot of different opinions fyi.

 

I usually use 24oz (2x12oz) buy one get one deals on Techron concentrate from local auto part stores. had best results with it.

I found other fuel treatment like Gumout Regane or Lucas Fuel cleaner or Valvoline fuel system cleaner to do very little, close to nothing.

I heard good things about BK44 also. myself I tried sea foam treatment on both cars with awesome results (regained acceleration and engines look cleaner under valve cover).

 

I usually use 24oz (2x12oz) buy one get one deals on Techron concentrate from local auto part stores. had best results with it.

I found other fuel treatment like Gumout Regane or Lucas Fuel cleaner or Valvoline fuel system cleaner to do very little, close to nothing.

I heard good things about BK44 also. myself I tried sea foam treatment on both cars with awesome results (regained acceleration and engines look cleaner under valve cover).

O'Reilly has another 2-for-1 deal for Chevron Techron concentrate. $8 for the 12 oz. Can't wait to see what kind of difference it really makes for my cars. If it works like everyone says it does, I'm going to stock up.

Oh yeah, I put Gumout Regane into my 22RE last weekend, and that thing idled like it was brand new in a day. Hard to believe a loud ass, sputtering-at-idle engine could be tamed by some little bottle of fuel cleaner. If only everything else was this simple. We'll see how it responds to Techron.

 

Go with Techron. It uses polyether amine (PEA) - a detergent that leaves no ash unlike cheap cleaners.
http://www.chevron.com/products/prodserv/additives/tcp.aspx

And use Top Tier gas like Chevron with Techron
http://www.toptiergas.com/
http://www.techron.com/

 

I use a can of Berrymans b12 after every oil change in everything I have owned. I have never had to "clean" the intake or throttle body etc in well over 500k miles.

http://berrymanproducts.com/Default.aspx?tabid=140

The newer cars seem to adjust to whatever fuel or additive I use as far as mileage is concerned. That is I think with normal non aggressive driving it won't make a whit of difference.

 

I used to use Techron a couple times/year. Never noticed a bit a difference so thought I was already clean and maintaining. Switched to BG44K, one can in 12 gallons ('93 Corolla 1.8L 5 speed) and mileage went up 3-4mpg and stayed that way (until I got into the gas since car had more power and redline came easier = more fun to drive). 220k "normal" highway cruising about 60-65mph and car would get 38-41mpg. Had same results on other family vehicles. I'll never buy Techron again as imo it was a waste, others swear by it. Maybe it helped to keep it from getting worse but I saw no change except a lighter wallet.

When I junked my car I yanked the head off. There was ZERO carbon buildup on any of the piston tops or valves. Fuel injectors were clean and shiny and that was after sitting for almost 3 years.

 

There was a lot of discussion a few years ago when they started using ethanol blends. The prevailing though was using acetone to improve fuel mileage but the affect on rubber/neoprene components was debatable.

If there were a truly good fuel treatment that can significantly boost mpg's - it'd be widely known and available.... and I'd want stock in that company.

The best you can do is perform DIY oil changes using a synthetic "0W-" weight oil, drive reasonably and keep your tires inflated to spec.

The DIY syn oil change allows you to extend your oil change intervals at a price near dealer charge for dino oil. The "0W-" will bump up your mpg's a bit. That's where you can gain some cost savings..... If you are a high mile driver, your savings are scalable.....and more noticable.

 

I heard good things about BG44K too. however it's not supposed to be used more often than every 60k miles or so I think. I am going to give it a shot before oil change (could be a while, running 0W oils in both cars). important thing about this treatment si to change the oil after the tank with additive runs oit. BG44K kills the oil TBN pretty quickly.
someone tested oil TBN after running BG44K and it came up as 0 (zero).

other than that techron is a great additive when used often in small quantities, like when you pump the gas from chevron/texaco. if you stick to tier 1 gas providers like Shell, Exxon, BP, etc. they use their own additive, so techron might not have much of effect.

 

My Lexus dealer cleaned my injectors and fuel system using the BG system. 04 ES. Very happy with it. My brother had his Ford Fusion done at a local shop and very happy also.

 

Bought my car with 97k...I have no reason to believe the fuel system was ever cleaned. Ran Techron through at ~107k miles. Zero difference in gas mileage or perceived performance. I use Wawa cheap gas. I don't think gas cleaners do much for most of your regularly driven commuter cars running ethanol gas, but if you use really cheap gas, it's probably a good idea to use one every once in a while.

 

I say don't waste your money on additives. MOST don't do a thing. Look at BITOG.com. many opinions on the subject.