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Gas Mileage Issue?? Help!!!

1K views 9 replies 6 participants last post by  bazross 
#1 ·
Hey all,

So I put in a new TRD CAI and TRD Exhaust on my 2013 tt FJ. Since I've done this, I've noticed two issues.

#1-i hear a constant whistle noise while having my car cruising at a steady speed. The sound goes away when i accelerate or decelerate.

#2- it seems as if my gas mileage has gone down drastically. I was under the impression that by changing these two things, it would in fact increase my gas mileage.

Anybody know any tricks or advice as to what to do? Im hoping its a simple fix that I may have overlooked during instillation. ***all parts were installed by a Performance parts mechanic whom i trust at***
 
#2 ·
#2- it seems as if my gas mileage has gone down drastically. I was under the impression that by changing these two things, it would in fact increase my gas mileage.
It could be a problem with your throttle pedal. In particular, it's possible that your foot is now pressing it harder. This is a pretty common problem when installing intakes and exhausts. The CAI and exhaust should have almost no effect on your MPG.
 
#3 ·
Maybe the parts that Toyota Engineering spent time and money on to develop the best gas mileage to bring the fleet mileage up could possibly be the best for that motor. Those guys in white coats in great big buildings with Dyno's,big computers,fancy test tracks,test drivers,years of experience and almost unlimited successful awards just may know what is best. Or not.


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#4 ·
Does the whistle noise come from the CAI or the exhaust? Intakes can be noisy, but usually on acceleration. The exhaust may have introduced some drone/tone that you are hearing.

I would not expect mpg to improve much, if any. Would not think it would decrease. Has you location switched to winter gas yet? My mpg goes down 1 or 2 mpg with winter gas.
 
#5 ·
well i have figured out a solution. I did appreciate the vast slew of sarcastic responses, but i communicated with the white coat wearing engineers and this was the solution. After a CAI & Exhaust are installed in a FJ Cruiser, its necessary to reset the ECU. The reason being is because the MAF (mass airflow sensor) needs to be reset to recalculate for having a CAI. The explanation i received is that the old intake does not allow as much air to get into the engine and with he CAI, it allows substantially more air into the engine. The car thus is used to having little air and causes the engine to burn extremely rich. The whistle was actually from my gas pedal throwing gas at the engine lmao. So whats the fix? Disconnect the batter completely for 30 minutes. After I completed the reset, the whistle disappeared and the gas mileage has returned to normal for the most part if not increased slightly! SO for anybody who changes any of these parts on their vehicle, make sure you reset the MAF.
 
#6 ·
I think most (all?) of the CAI instruction manuals will tell you to disconnect the battery before installation. They probably tell you this for safety reasons but, it has the added benefit of doing what you described above. Which, amusingly, is probably what most people are actually seeing when talking about "power gains" from a CAI.

(I know you didn't talk about power gains from the CAI, just throwing that out there)
 
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