2011 TACOMA GETTING 10MPG!! please help

Usually lean/rich codes won't set until around +/- 15-20% total trim.

General rule of thumb is MAF g/s at hot unloaded idle is pretty much the same as engine displacement in liters, so 4.0l should read around 4.0 g/s.

I'm curious, has the K&N CAI been on the whole time or did the problem start after it was put on?

I'm asking because I've seen aftermarket air intakes not being the same diameter or design as the OE and skewing the MAF readings.

 

So at idle (650-750rpm) it’s saying 0.5lb/min to 0.6lb/min
The cold air intake has been on there ever since I purchased the truck.

 

Did you just oil the K&N as excess can get on sensors and screw up readings.
Also there is a larger vac line on the front by the throttle body and mine was loose as end distorted so I cut it slightly shorter for a better fit and added a clamp.

 

What type of spark plugs did you install? If you installed iridium, I'd get a set of Denso, NGK or some other flavor of standard copper plugs and install those.

 

I got them from the dealership. I think it was Denso or NKG. I got iridium’s at first then shortly after realized those are incorrect for Tacoma‘s.

 

I put in Iridiums last time and have no problems with them. MPG didn't change and I feel it ran better right away? Could be because the ones I pulled had about 35k on them? I did a lot of research to get the correct ones. I never get 300 mi per tank unless I do a lot of hwy miles which I dont. Mostly around town but I have some added weight 250-300 lbs or so. I average about 15mpg mostly around town and short trips. I'm curious to see what might be the problem since you've done the obvious stuff.

 

A lot of those plug in type fuel controls mess with the programming. Have you unplugged the battery for 10 minutes, then plugged the battery back in, and let the engine go through a relearn process? That’s what I would try.

 

Sounds like you still have summer air in your tires and need to replace them with fall air.

 

This is such a myth. There’s no such thing as fall air, just winter air.

 

Yes, I did that 2 months ago and got a lower idle rpm but same gas mileage

 

I use co2 to fill my tires so it shouldn’t matter. At least I think….

 

This was my thought too. A thread on fuel efficiency and "replace air filter" was not mentioned.

This thread kind of reminds me of the unicorn sticker thread from several years back.

 

@fsbrain03 might find that comparison highly insulting.

 

That’s pretty close to normal.

I guess the next thing to look at would be A/F and O2 sensors.
There’s a reason your trims are above 10%.

 

How do I check those? Just take it off and visually look? It’s not throwing any codes so I don’t know what to check for.

 

Could they have changed to the Winter Blend of gas already in your area and that's why the drop in mileage?

 

The difference in energy produced is something like 2% less…

 

I was just throwing that out there, Wasn't sure if that would have made a big difference or not.

 

I get 10-12 on my 2021. My tires and my right foot are my problem.

Have you tried helium in the tires? It reduces the weight of the truck by half and increase horsepower and doubles mpg. Great at parties too.