VERY new to this platform so bear with me; I'm sure this topic has been covered extensively but what I learned just this morning seems to have solved the problem.

Jeep: 2017 JKU Rubicon, 76K miles, 6-speed manual, 37s on 4.88s.
Problem: the engine stops accelerating/revving after approx. 4100rpm in any gear. This is terrible when trying to accelerate into freeway traffic or pass on a hill/headwind or just trying to get over or up an obstacle. The engine has been running flawlessly with zero engine codes or other issues beyond this one.
Research: a google search returns many threads and discussions, some from this platform, that seem to point to anything from a compromised seal between intake plenums to crank position sensors to I dunno... whatever else. I was planning to pull the intake off when I got around to buying/replacing the oil cooler and installing the Baxter Performance spin-on adapter, figured I could reseal the whole thing.

Today I installed a cat-back exhaust and cold air intake. The latter has a sensor plugged into it called the Air Charge Temperature Sensor (Autozone part #SU18256). This sensor has been misidentified in YouTube videos as the mass air flow sensor and by my local Jeep dealership parts counter as the manifold absolute pressure sensor. Based on what I found it is neither and is in fact, the air charge temp sensor. I have not seen or heard this sensor suggested or identified to solve this issue previously. The one I took out of the factory air box tube was bent to one side and while trying to straighten it out, broke one of 2 wires at the tip. It tricky even getting it out of the air tube: it requires prying a tab up and rotating the entire sensor counter clockwise with a pair of pliers.

Anyway, I finished installing the new sensor in the new air box tube, installed the whole thing in the jeep, and went for a test drive. It was immediately apparent that this solved the initial problem: the jeep pulled hard well above 4K and never stumbled a single time. This allows me to really hear the new Banks Monster system I installed and makes me smile. Given the fact that no other sensors or settings or engine adjustments were made, I feel fairly confident this was the culprit. And since it's FAR easier to access and check than pulling the top of the engine apart, I think it's important to spread the info. This saved me hours of work and most certainly more than the 60 bucks this sensor cost me.

Photos


Factory air charge temp sensor.

Top view of the air box tube as it sits in your engine. The throttle body attaches at the right end of this tube, air filter off camera to the left

Air box tube tipped towards you, the sensor plugs into the little spigot just left of the band clamp.

This tab must be pried up while twisting the sensor counter clockwise to remove.

Here's the auto zone replacement part, #SU18256, $58.99 in AZ.

 

Very interesting and informative.. Good post !