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WRX blip hesitation while medium to hard acceleration

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6.8K views 12 replies 6 participants last post by  nsibanez  
#1 ·
My new WRX, 1000miles, has an annoying quirk. While accelerating, moderate to hard, there is a momentary hesitation, or blip or 2 while moving through the power curve. It feels like momentary fuel starvation or possibly the waste gate opens for an instant. Is it only mine?
 
#2 ·
Welcome to the forum.

I've had similar issues with different tunes I've tried. For me, it would feel like a flat spot. My problem would actually be on the low boost/rpm side. I'm not sure, but maybe it's possible that the car is still learning. I've attributed the flat spots to the car being used to WOT, and predicting such conditions. For example, it is expecting me to drive aggressively, so when I'm not accelerating hard, it's not sure what to do haha.

Depending on how you drive, maybe it's just the computer learning (new driving conditions + environment)?? But again, I'm just guessing. Without any videos or engine codes, it's hard to say.
 
#3 ·
Thank you for the response. It makes logical sense and since it is so new and been light-footed for 1k miles, it is going through a learning curve :) Me too, my first Subie… (not my first rodeo), but this is different and I love the car.
 
#4 ·
The problem is with the ECU mapping, the new Cobb Access port will take care of it. I'm getting one as soon as funds are available.
 
#5 ·
Please for the love of your subaru, do not ever use a Cobb OTS map!
 
#6 ·
Its the stock ecu, mine did the same even when I bought it with 28k miles on it. I went away after I started modding and went to a custom map.
 
#8 ·
The off the shelf map from cobb is a "universal" so to say map for each stage (one and two) for every car to run. It's safer and better efficiently to get a pro tune as it's specific to YOUR car with any environmental and driver habits and will vary on each car regardless if it's the same year and model.
OTS is quick and simple but can lead to hit or miss problems such as boost creep/spike
 
#9 ·
If your car is hesitating in the middle of acceleration it may be knocking and pulling timing. IDK because there isn't enough details plus you would need someway to monitor knock to know for sure. What rpm is this occurring at? What gear?
 
#11 ·
But if it's the stock tune, from my experience that's how they are...They're not smooth through the power band. From my car with 110k on the ODO and test driving a brand new at the time 14 with an old Co worker...same thing. From what I remember it has to do with keeping the car from running too lean? Either way it's normal until it's tuned (assuming that's his only issue)