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Old 05-07-2019, 12:49 PM   #1
hangten202004
Scooby Newbie
 
Member#: 501273
Join Date: May 2019
Default 2018 STI hesitation issue(s) (15k miles)

I have been experiencing a weird shudder/hesitation (for about a month) and the boost gauge goes bonkers while doing WOT in low gears. While in other gears it performs just fine. 4th-6th works fine see below for more descriptions. On cold starts the car performs perfectly only happens when the car gets warm after about 20 mins of driving. Also, I am getting zero engine codes.

SI mode: does it only in 1st and 2nd
S Mode: does it in 1st, 2nd, and 3rd
S# mode: does it 1st, 2nd, and 3rd

++++Note++++ This only happens after the car gets warm (20 mins of driving).

Mods:
COBB SF+ Intake with accessport
v346 Stage 1+ SF 91 ACN map
Borla S-Type exhaust
COBB stage short shifter
COBB turbo heat shield

I have inspected visually for loose hoses, and leaks. Found nothing. I took it to the dealer and they can't/won't do anything because of the accessport.

Things I have tried/tested:
1) re-seating intake
2) cleaned MAF sensor with MAF cleaner
3) re-seating TMIC - still happens
4) inspected hoses/vacuums - found nothing
5) re-flashed about 70 miles ago - still happens
6) tested stock map - performs worse
7) reset ECU - still happens
8) tried using fuel cleaner when did a fill a couple weeks ago - still happens

Any idea what it could be or what to look for or what else to try(replace)? My car has about 15k miles.

Any help/advice will be greatly appreciated.
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Old 05-22-2019, 04:37 PM   #2
hangten202004
Scooby Newbie
 
Member#: 501273
Join Date: May 2019
Default

bump.
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Old 06-02-2019, 07:34 PM   #3
Leigh2011STI
Scooby Newbie
 
Member#: 502810
Join Date: Jun 2019
Location: Toronto Ontario
Vehicle:
2011 STI
Pearl white

Default

Sounds like issue with the throttle body. Mine was doing that a couple months ago.
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