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Discussion Starter · #1 ·
As the title states, my engine will not rev past 2500 RPMs. Once the engine hits 2500 RPMs, the whole car jerks and the engine behaves as if it's being "choked' and not getting fuel anymore.

I have a base AWD 3.7 Q50 with about 3600 miles on the clock. This happened last night and the check engine light came on, but I did not take it to the dealer until this morning due to lack of loaner car availability. I literally did not go over 40mph on my drive to the dealer. As long as I didn't rev the engine above 2k RPMs, the issue didn't happen.

Dealer has yet to get back to me on the diagnosis yet. They just acknowledged the issue is 100% reproducible and they needed to keep it overnight.

I've had 2 G35 coupes, 1 G37 coupe, 1 G35 sedan, and 3 G37 sedans and have never had this type of issue nor have I read about this type with the VQ series engine.

Has anyone ever experienced this problem?
 

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Ya I had it before while test driving a '07 G35x.
 

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I had the same issue a while back with my Q50S except it didn't have a check engine light or choking issue. Mine was the sensor that interacts with the brake pedal was sensing that my foot was on the brake all the time even though it wasn't and the car would only go up to 2500 rpm. I figured it out when I noticed the 3rd brake light on in the rear while the car was off. Quick fix was to adjust the sensor by the pedal.
 

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I had the same issue in my Honda. It went up to 4000rpm won't change gears and would jerked, I always had an obdii reader on hand and disabled it and the car runs fine briefly after that. The problem in my car ended up being that the idle air control valve was dirty so I cleaned that with carb cleaner and cleaned the throttle body, worked fine after that
 

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Discussion Starter · #6 ·
Dealer finally called late last night and said it was a valve timing sensor failure, and the reason the engine is being "choked" is due to fail-safe mode to prevent any damage. The dealer couldn't reach the Infiniti tech line, so they will have my car at least another day to fully diagnose. Not sure if new parts are needed or not.

In the meantime, I am enjoying my G37x loaner car. Forgot how much fun it is to drive. Definitely raw and unrefined compared to my Q50, but still a hoot.
 

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engine sounds like being choked and wouldnt pass 2500 rpm

what was outcome of the problem from dealer pin point? i m facing the same problem with my 2015 q50 now and since its a rebiult title i m not eligible to warranty anymore car have 6k miles only :(
 

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It's called limp mode. It's designed to keep the engine from destroying itself if there is a malfunction. Have your engine check light read an auto parts store, and if there's nothing major, Do a full factory reset (pull the battery cable step on the brake four or five times, reconnect the battery cable) and all should be right with the world.
 
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