Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - P0303

hachigoku · 10-13-2021, 01:08 AM

Hi! Need some help with a returning P0303.

Some historical events -

My 13 BRZ (2015 FA20 swapped) threw a P0303 last month and I took action by replacing the spark plugs and the coil. Both plugs and the coil are OEM from a Subaru parts center. Did the job and reset the code. Everything was great, I even got an MPG improvement. Drove 300 miles and still great.

Today -

Went to Laguna Seca to do a track day and my first two sessions went well. During my third session, the car started to have a distinct rumbling exhaust note, power loss, and blinking CEL. Pulled into the paddock, turned off the car, and checked for the code. Code was P0303. I decided to pack up and leave. I cleared the code before leaving.

On the way back home, the symptoms came back and it struggling. At times the issues were intermittent, it was struggling/bogging and then things feel fine for a very short time, within seconds. Then goes back to the struggling, bogging, power loss, blinking CEL, and rumbling exhaust note.

I'm starting to think that cylinder 3's injector is bad. Not totally sure though and I don't want to start chasing a problem blindly. I did some data logging on my OFT v2, but I have no clue how to read it.

Here is my data log:

https://drive.google.com/file/d/1jPV...ew?usp=sharing

---

Relevant aftermarket parts for the P0303.

JDL Catted UEL
Stage 2 OFT OTS Tune
Tanabe Over Pipe
Tanabe Front Pipe
GReddy SP Elite Cat Back

Would love to get some insight from my fellow 86 owners.

10-13-2021, 01:08 AM	#1
hachigoku Member Join Date: May 2017 Drives: BRZ, E90 M3 Location: San Francisco, CA Posts: 50 Thanks: 3 Thanked 8 Times in 5 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	P0303 - Engine Struggling and Rumbling Hi! Need some help with a returning P0303. Some historical events - My 13 BRZ (2015 FA20 swapped) threw a P0303 last month and I took action by replacing the spark plugs and the coil. Both plugs and the coil are OEM from a Subaru parts center. Did the job and reset the code. Everything was great, I even got an MPG improvement. Drove 300 miles and still great. Today - Went to Laguna Seca to do a track day and my first two sessions went well. During my third session, the car started to have a distinct rumbling exhaust note, power loss, and blinking CEL. Pulled into the paddock, turned off the car, and checked for the code. Code was P0303. I decided to pack up and leave. I cleared the code before leaving. On the way back home, the symptoms came back and it struggling. At times the issues were intermittent, it was struggling/bogging and then things feel fine for a very short time, within seconds. Then goes back to the struggling, bogging, power loss, blinking CEL, and rumbling exhaust note. I'm starting to think that cylinder 3's injector is bad. Not totally sure though and I don't want to start chasing a problem blindly. I did some data logging on my OFT v2, but I have no clue how to read it. Here is my data log: https://drive.google.com/file/d/1jPV...ew?usp=sharing --- Relevant aftermarket parts for the P0303. JDL Catted UEL Stage 2 OFT OTS Tune Tanabe Over Pipe Tanabe Front Pipe GReddy SP Elite Cat Back Would love to get some insight from my fellow 86 owners.