Seafoam has been proven to work..

Never used BG..

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Oh 100% correct. The 10% ethanol actually hurting our mpg on our rigs. Our systems were designed for 100% gasoline. Granted the engineers at toyota stated that the older engines should run with up to 15% ethonal in the gas without damaging things that's a 5% more loss in mpg.

I honestly think this is the cause for the fuel system issues.. the ethonal is eating the deposits out and clogging the filters and injectors. As this makes the most since with the age of the rigs and why people are having to clean and replace the injectors.

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Different experiences here. My first fuel injected Toyota was a new 1984 Celica GTS. Aside from two budgetmobiles (1979 Corolla and 1987 Tercel wagon), I've had nothing but fuel injected Toyotas since then. Most of those were driven past 200k miles. I never had a fuel injector problem, and never used any additives. So maybe I'm not the norm here.

To add to what's already been said, run some cleaner through, it will be best while the filter is still fresh as can be. My favorites are Red-Line SI-1 and BG44k Platinum. Both are excellent combustion cleaners as well; feller I knew ran SI-1 through constantly for maybe 3-4 tanks, then gave it a good ol italian tune up for a good 10 minutes (and changed oil for good measure). Pistons were nice and bright afterwards. Could've been a thin layer to begin with, but I've been a firm believer ever since. If you can, go out of your way for some ethanol-free gas, you'll be amazed at how much your 4runner likes it. All just my 0.02

Semi-related I also recommend try running some Marvel for the entire duration of your OCI. Rotella T6+MMO is absolute gold.

I know this is an old post, but I'm curious did you ever try the Red Line S-1 or the Techron?
I assume it's bad if we put multiple injector cleaners in the tank when the gas is almost empty, before refilling and driving it more.

I have not, maybe others have. I have only used Locus fuel injector cleaner and sea foam, others have thought that doesn't work well. Could be right. I haven't used other projects I know sea foam cleans carbs and other things very well. I would imagine any injector cleaner is better then none. The fuel is sometimes not the cleanest. So fuel cleaner on occasion. Others May have different thoughts on the subject as well.

I've changed my fuel filter 3 times over the past 11 years and I don't recall ever seeing any noticeable change in my overall mileage. I've run a handful of injector cleaners as well but nothing that I swear by or believe to be improving the cleanliness of my engine/fuel system. Every once in a blue moon I may run something through my tank like Lucas or the Techron stuff. I've heard great things about BG44K and I think I might have used it once before.

On another note, I am finally able to fill up exclusively with non-ethanol gas, so I'm curious to see how that will affect my mileage after running through a few tanks of it. It's definitely way more expensive that any other gas near me, just short of $4.00/gal but if I'm able to get significantly improved MPG's with it then I might just stick to the stuff.

Perhaps switching gas brands once in a while and adding different injector additives a couple times a year will allow the different ingredients to complement eachother?

The stock ECU ignores the knock sensors below ~3k RPM, so it is unlikely to have much of an effect on MPGs. Mine is just on the verge of knocking with 87 at low-ish RPM and high-ish loads, so I just switched over to 91. The $0.20-0.40 difference in price is minimal compared to the overall price of gas here (yay California).

-Charlie

Over the years I've changed the fuel filter, had fuel injector service at a Toyota dealership and used Techron to try and smooth out some roughness in the idle, with no discernible effect. During a recent valve cover gasket replacement, I removed the throttle body and thoroughly cleaned both sides of the bore and throttle plate, with Toyota throttle plate cleaner. What a difference a clean throttle body makes. The idle has smoothed out to like new. Don't know what it will do to my gas mileage but hoping for the best.

For a good gas mileage check the coolant temp sensor (2 wire) located right under the fuel rail and behind the timing rear cover is in correct spec (2000 to 2400 ohms cold and 300-400 ohms when warm). It controls the fuel injector pulse width and ignition advance/retard.

I can say from experience that the stock fuel system can handle up to roughly 50% ethanol before the fuel trims max out adding fuel, and the CEL comes on. This is on a "California Emissions" style rig with the 2 catalytic converters and Air Fuel Ratio upstream sensor. I'm not sure what the capabilities of the narrowband ECU rigs are, I'm thinking those might have less fuel trimming capability but I'm not completely sure on that. I experimented with E85 on the stock fuel system while naturally aspirated in preparation for the turbocharger. I then installed a 255lph fuel pump, 315cc injectors (29% larger than stock) and filled up with E85 (requires ~30% more fueling than gasoline), and it worked like a charm. Fuel trims were in the low single digits. After a few hundred miles I replaced the fuel filter just for good measure in case it cleaned out any gunk from the fuel tank. I'm not sure that there was any real gunk in there to begin with, as gasoline is a fairly good solvent anyways and I didn't notice anything when I dropped the tank to replace the fuel pump.

@nissanh Thanks for the tidbit, temps dropping into hi 20's has brought a new quirk this year.