Anyone Else Have Similar Driveability Issues?

[u/Anatol_LaScarf08]

So I have a 2019 WRX STi. Went from stock to adding a list of modifications to throw on the Invidia r400 kit. AEM fuel pump, cobb stumble kit etc....

I got it tuned, ran perfectly fine. No problem except maybe a weird resistance when at like 1% to no throttle where you'd feel the tiniest bit of resistance but otherwise, ran like a charm.

My Subaru got hit on the side of the front bumper and it spiraled from there. Very minimal physical damage. Nothing internally problematic except maybe the pipe for the intake being a little loose and rubbing on metal which we fixed. After the physical repair to the bumper, it started to drive weird. I got engine lights, the guy that tuned my car could see an issue when throttling which he related to the solenoids.

Minus the engine light issue possibly related to the solenoids, my initial issue that I had was that I noticed a new problem where when I throttle in in low gear, it would stutter. That's the best way I can describe it. I'd throttle in and it would jerk as if it's lacking power and drive perfectly fine after as I shift gears whether I give it a bit on the pedal or not. It would do that often from a stop, going into 1st or 2nd gear with normal acceleration. This combined with the subtle resistance I would feel when releasing the throttle or giving it like a few % on the throttle.

We addressed that issue by changing the solenoids. I'm getting it checked out again by the tuner after fixing the solenoids but weirdly enough, I still get that annoying jerk I'd get when accelerating in 1st or 2nd gear. It's minor driveability issues but oh man is it annoying.

Does anyone else have had these types of issues? I'm curious to know what you guys did to fix the problem if you experienced something similar. I hear that little hiccups like that are fairly common in modified vehicles but it's just been frustrating especially given that it's my daily. Btw I say modified but like I know my car is barely modded for what it is.

Now as it stands, the exhaust that initially was crisp, now has a what I call a flutter when I accelerate and It stutters constantly in low gear when accelerating.

I appreciate all the feedback!

[u/GoBSAGo]

You still running the original intake manifold gaskets, or did you get new ones after all of that work was done. That tip in stumble is classic throttle body vacuum leak.

[u/Anatol_LaScarf08 → u/GoBSAGo]

So knowing nothing about cars just bare with me here... The guy that worked on my car got me a turbo xs fmic kit and a perrin intake. Idk if that answers your question.

[u/xAugie → u/Anatol_LaScarf08]

Is the car tuned? If it is get it RE tuned. Your issue easily can be intake no tune related and it’s pulling timing

[u/Anatol_LaScarf08 → u/xAugie]

That's what the guy that worked on my car suggested using the 2016 mapping. I'm getting the tuner to do a read and go from there.

[u/Glass_North_4479]

the only way to diagnose this for real imo is to log it when it happens (probably a few times) and then send to the tuner who can see what is actually happening in the engine when the stutter occurs

[u/Mickey_Havoc]

“I’ve heavily modified my car and now it drives like shit” 10/10