MPG loss after TRD air intake install..?

Hi Folks,

So, I made two upgrades at once and afterwards noted a fairly significant drop in MPG. I installed the trd intake and also installed OVTune and now most in-town trips get as low as 8 mpg.

I flashed OVTune back to the factory stock flash and still get low MPG. Also, most users noticed an increase in MPG with OVTune. I'm thinking it has something to do with the intake.

What might I have screwed up when installing the intake? Any sensors or anything that I might have damaged during install? The filter itself looks nice and clean.

Where should I start looking? Thanks.

Added: Another change I made was that I switched from 87 octane gas to 91-92.

 

Wow, 8 mpgs that really sucks. Hard to belive intake will do that. I read the ov tune review thread and all members said they got improvement in mpgs.

Any warning lights on? How does it drive? If you didnt connect sensors right you would def have warning lights on. Very curious to know whats the issue. Good luck and hopefully you fix it soon.

 

I guess one more change I made during that time was going to 92 octane gas from 87...for the tune.

 

*points at your foot*

 

How many miles since the change? It took a solid ~400 miles or so before the tune really settled in and i started noticing a improvement in MPG. When you flash the ECU, most if not all the fuel and timing trims are reset, which will in turn need to be relearned. Give it some time if you havent already.

FWIW I got about 1 mpg increase with the tune over stock (87base tune) and average ~19 mpg. All stock, except for 250lbs of armor and 265/75r16 10 ply tires that are very heavy.

 

The TRD CAI I put on my gen 2 netted me a slight mileage increase. This is very strange. Try disconnecting the battery negative for about 30 minutes. MAF clean? Throttle body clean?

 

I have the TRD intake and mileage was the same as stock. Maybe a hair better if anything. Have had it for about 15,000 miles

 

So we are all in agreement that something is "wrong" about this.

I don't have any warning lights on. I do periodically feel a misfire or two, but Mat is addressing that issue with his OVTune updates. I'm tempted to replace the MAF sensor just to rule that out, but not sure if there are other things that can get screwed up with this install.

I seem to recall reading somewhere something about these air boxes blocking an injector something something but don't know where or what that was.

 

You can try cleaning the MAF sensor first. Make sure it's cold before you start and use MAF cleaner.

 

The second gen tacoma black and red plastic topped "trd" intakes typically run lean... So that makes sense

 

^ seconded. MAF clean may be in order, but generally as a rule if the MAF is faulty you'll get a CEL coming on. That being said, due to there being a new intake in question, still would be the first place I'd check.

 

I just installed my TRD CAI last saturday and flashed 1.05 87 base on thursday. my mileage stayed about the same. if you are getting 8 MPG I think you would smell the catalytic convertors (rotten egg smell) from an overly rich mixture. make sure you didn't over tighten the clamps on the plumbing to the intake - they just need to be snug enough to hold the hoses on. if the maf sensor was not plugged in you would have warning lights at a minimum. the only other thing that is disconnected to install the CAI is the EGR hose - that's easy enough to check. other than that reflash to a different tune and disconnect the battery or refill the tank to reset mileage. how many miles driven since the changes?

 

Did you take the plastic off the filter?

 

I like it.

 

Are you waiting a full 300-400 miles after a flash before you start watching mpgs? This is crucial

 

I can't even imagine 8 mpg in a Tacoma. My worst mpg so far was 17.1 mpg and that was due to driving into 25 mph headwinds coming out of the Columbia Gorge combined with making a half dozen trips to the hospital in The Dalles which I swear sits on the highest hill in that area.

One should not go by what you see on your dash readout. The one and only way to tell if your mpgs are actually worse is to have tracked all your mpgs per tank prior to making the changes and then continue doing so afterwards. Total miles driven divided by gallons to fill the tank. The only way to see trends.

 

87 octane has more btu per gallon than 91. Likely it’s the tune and required fuel.