2015 getting awful mpg...help!

You have V6, so.... no.

 

So if the 4.0 L engine is designed to run with 91 octane, why doesn't Toyota say that? Doesn't make sense to me. Recommended fuel for 2015 is 87 octane.
https://pressroom.toyota.com/releases/2015+toyota+tacoma+product+specs.download

 

Unscrew the gas cap and look on the TOP edge of the opening. You will see a hole, which is the vent hole that leads to the charcoal canister. Observe how that hole is ABOVE the lowest part of the opening. In order for liquid gasoline to exit that vent, it would definitely spill out and onto the ground. Even then, it might not go out the vent.

This whole "stop after the first click" thing is nonsense. Manufacturer recommends it to avoid making a MESS with gas handles that are under-sensitive. Those who claim to have had problems with the evap canister right after the first time they tried to go for click #2 either experienced a coincidence, or has formed sympathetic memories after reading about it happening.

At 5 years ownership now, I **ALWAYS** keep on filling until the $$ value goes even "$xx.00", still no xmas tree lights annoying me about the charcoal box.

 

I think the deal is that it adjusts the timing if it detects pinging, which can occur with 87 in some instances. Typically low elevation, high ambient temperature, and use of high throttle position.

 

My 2010 V-6 is also a recommended 87 octane engine, per owners manual... as was my 2005.

 

I didn't get any lights on the dash either, just a code that was stored in memory. I wouldn't have said it if wasn't true, no need to lie about it. The way I see it is if the potential is there why risk it? Does getting to that coveted $xx.00 really matter?

 

Getting a good "average MPG" is like playing the stock market.....You are in it for the long haul. An itchy trigger finger accomplishes little. Just keep records and look at average over 10 or 15 tanks.

Being OCD about ANYTHING is semi-useless. I try to round off $$$$'s on fill ups, but there's nothing in the rule book that says you can't stop at $XX.50 or some other number.

Don't sweat the petty things.....or is that don't pet the sweaty things....

 

I've already posted the engine specs for you. The 4.0 has a compressions ratio of 10.0:1, which is fairly high, meaning best performance will come with higher octane. The computer will detune itself to run 87, but it can develop a knock, especially if you're doing any work with it.

The 1GR-FE is the 4.0 L (3956 cc) version, designed for longitudinal

mounting in RWD and 4WD pickup applications. It has a 94 mm bore and a stroke of 95 mm. Output is 236 hp (176 kW) at 5200 rpm with 266 lb·ft (361 N·m) of torque at 4000 rpm on 87 octane, and 239 hp (178 kW) at 5200 rpm with 278 lb·ft (377 N·m) at 3700 rpm on 91 octane. This engine features Toyota's VVT-i, variable valve timing system on the intake cam and a compression ratio of 10.0:1. Service weight, including fluids, is 166 kg (366 Lbs).

 

He knows

 

You have that owners manual handy? Someone told me that once and if I remember right they quoted the research octane number.

 

I always pay at pump with CC so no need to get to an even amount. I just stop at first shut off.

 

I agree, but you keep telling me it adjusts the timing 100% of the time with 87, which is not what He said. You finally agree?

 

Well it's going to detune itself which includes retarding the timing

 

I will bring the manual in and copy it here on that page... I could be wrong as it has been 6 years since I read it? Others have posted the same, however. I think the 4Runner with the 4.0 had an 89 octane or 91 octane recommendation? There was chatter why the same engine had two recommended octanes depending if it was in a truck or wagon.

 

87 octane or higher (in 2010)

 

^^^ Same in my 09 owner's manual

 

Not all the time as you agree, but what else would you say is going on with this detuning besides retarding the timing?

 

Most likely timing and fuel map. I'm not a Toyota software engineer, so I don't know how they get it to detune itself. But to keep it from knocking, fuel map and timing would be the way to do it

 

I think that the disconnect is probably in the question of what it means to retard the timing. In the very very old days, timing was fixed. Then there was a mechanical device that could adjust the timing based on throttle position. It was pretty simple. Then ignition went electronic, and it used the throttle position sensor to apply a still-linear offset in about the same way as a mechanical shift. NOW, we have very sophisticated programming that is able to adjust the timing relative to the base timing curve in the particular region of status and input conditions as needed.

In other words, if it pings only above 5000 rpm at WOT, then it will only retard the timing above 5000 rpm at WOT. Everything lower will run on the standard timing curve and yield the same output characteristics.

 

Yep, as you said before tgear.shead, many things determine whether pinging will occur with a given octane. A V6 running at Denver altitude isn't going to ping with 87 or 91, doesn't matter since the cylinder pressure will be 15-20 psi lower than at sea level.