3G Tacoma, Reduced torque and lwoer MPG with less restrictive exhaust?

Hello all,
I have a 2020 Tacoma v6 3.5L and am wondering if installing a less restrictive exhaust may have been determental as it feels like I may be getting lower MPG (currently getting around 15.8 mixed city/hwy with stock tire size) and lower torque under ~2500RPM

I had the stock muffler replaced with a 2.5" Carvan TR and a 2.5" Vibrant Ultra Quiet, which is most likely less restrictive then the stock muffler was.

I'm generally pretty light on acceleration.

Am I likely imaging things or would I be best having the OEM muffler welded back on or getting something like the Magnaflow Overland exhaust which is pretty well reviewed but seems to still have some backpressure to it?

 

15.8 is lower then I was getting towing a Jeep Cherokee. Did the performance/mpgs tank after that replacement or has it always been lackluster then? I went with the TRD exhaust as it got a slightly nicer note but isn't annoying (to me) and the performance was "fine". Most of us just tune the ECU/TCU to fix all the throttle delay and shift problems for <$500 and call it good to round it out...even with the stock exhaust setup most owners rock it's got plenty of power once calibrated. I say swap it back and see, then we can tune it!

 

I did also get it tuned with OTT in that same time period which does complicate isolating a direct cause as to whether it's related to the exhaust, tune or just driving habbit change. I was averging ~17.4-18mpg before then though

Unfortunately, swapping the stock exhaust back on would involve paying the muffler shop to cut off the aftermarket stuff and weld in the OEM one plus a segment of pipe as it wasn't a bolt on swap.

I do notice that I have to generally get the RPM up to 4-5k RPM in order for the vehicle to pick up speed on the highway as gradually pressing harder doesn't seem to do much, I have to press substantially harder which then causes the transmission to drop a gear and the fuel economy to tank, which I suspect could be related to the OTT.

Running Lite/Mild.

 

If you need help troubleshooting I'll gladly assist. We can revert to stock and even try the latest and greatest tune (McB Elite Performance). Big thing is getting it identified for options. Glad to help if you want to reach out during daylight hrs and review options with me, perhaps it's not the exhaust at all. #757-320-2628

NOTE: Fellow owner support and discussions are always free and sometimes a 2nd opinion makes all the difference! Either way, I hope you get it cleared up as that is a hit for sure!

 

William,

Reach out to the retailer that initially tuned you with OTT. We can help you get answers to your questions without spending money needlessly.

To contextualize what is likely happening here, a cat-back exhaust doesn't contribute to what you are experiencing. What's likely happening, and depending on the specific timelines at play here, many areas start changing to a winter blend fuel every year, which can cause MPG to drop a few along with some of the initial grunt you had with non-winter blend fuel. Or you've just got an unlucky sour tank of fuel. The symptoms you're describing are consistent with each case of this we see.

We can confirm whether or not this is the culprit; reach out.