Dillon

That would be appreciated. I've currently gone to a FPR by Fuelab and bypassed the fuel pump control module so the pump runs at 100%. I'm hopefully getting a re-tune early July

That's what I fear the most. I would like to hold on to some hope lol. What about people with after market engine management? Could it be due to a flaw in the the stock computer, coding, hardware, chips, solder joints? I've even scoped the crank shaft and camshaft signals looking for interference or electromagnetic induction, thinking it could be due to poor engine harness engineering. I bought my 05 lgt bone stock, and I don't remember it acting like this stock. So I feel it's either something I did, something that is no longer working properly or even deterioration of electrical conductivity or connections. I will say that there is one thing that I have still not understood. If monitoring the avcs degrees, right after reseting the ECU (before it initializes/learns its "0"/home), the left(driver side) intake camshaft will read 7° off. This has led me down a rabbit hole. I even sat down and counted the cogs/teeth on my timing belt to insure I was installing it correctly. I hate how the left bank doesn't completely line up with the timing marks. There are company's that make offset/adjustable timing belt idler pully's to adjust for decked heads and head gasket thickness. But I have not purchased one to find out if it helps. I've also wonder if the UEL exhaust manifolds cause some sort of unpredicted scavenging effect at the infamous 2.5k rpm. There has to be an answer. Just because it's a "subaru thing", doesn't mean it can't be fixed.

If you have a way, monitor your avcs advance. You might have a bad avcs ocv solenoid. I have one go bad and it had some pretty bad bucking issues. It never threw a code or CEL, but the computer would stop operating it anyways. Maybe it didn't like the resistance value it was seeing. Beats me, but replacing the ocv solenoid fixed that specific issue. Good luck on your trial and error. These subaru's are a love, hate relationship.

It's very possible that I over oiled it, but I can't be sure since it's been about 5 years since it got tuned. I'm just trying to remove all the variables so the car can get a proper data feedback during tuning.

I'm soon going to get a retune also. I'm switching back to a paper panel filter. I think the K&N messed with the maf during tuning. I'm also currently researching the fuel pump controller and bypassing it. I know how I will do it, if I do it. But I'm looking for pro's and con's.

Absolutely!

Perfect example! Too bad it took me over 5 years to learn this myself. I've dealt with a stumble for far too long. Alot of stock and replacement pump assemblies only come with one! So everyone can be effected by this.

Yes. I'll look to see if I have a second o-ring and retake the picture to avoid confusion. Unless someone can photoshop a second oring stacked on top of the first.

Make sure you don't have a post MAF, Pre-turbo air leak. I suggest replacing at least the damaged o-ring, if not both. Unless, you only have one at this time, then I would suggest adding a second. I used silicone lubricant during install. Making sure damage wasn't going to be caused during install.

The picture is to show how it was previously. I have since added a second o-ring. Sorry for the confusion.

I FIXED MY STUMBLE! (Hesitation, stutter, hiccup after shifting (MT), rough acceleration. TYPE OF STUTTER/STUMBLE Steady throttle/Increasing throttle/Both: Initially only at steady throttle around 2k-2.5k RPM as a light bucking/stumble/surge of power loss. Then became evident in a wider RPM range and throttle input, along with a loss of smooth acceleration. MODS Intake: Stock airbox with K&N panel filter and silicone turbo inlet. REV9 TMIC with silicon throttle body inlet. Crawford AOS. Exhaust: No name turbo-back. Gutted up-pipe. Fuel: TREperformance 255lph fuel pump. K&N inline filter. Stock fuel rails ran in parallel. AUS 750cc injectors. Fuelab universal FPR. Turbo: BNR 16g with billet compressor wheel. Engine Management: Stock ECM with Cobb accessport. Tuner and revision of tune(if you don't mind): Stephen Clark at iaTUNING MAINTENANCE: 5w40 euro oil. Sensors changed: AVCS oil control valve solenoids, crank sensor, cam sensor, MAF sensor, throttle body, accelerator pedal assembly, knock senor location. Plugs changed: 1 step colder ngk's. Coil Packs changed: YES, a few times and even bench tested them to check the KV output. OTHER SYMPTOMS: Occasionally had a very low idle. Happened more often if the ECM was reset. Check Engine Light: No. Not even when I actually had an AVCS OCV that the ECM didn't like and would stop modulating it. Unplugged it and plugged it back in while holding the RPM around 2.5k and it would momentarily work again for a few seconds. Etc: I always use premium gas. I tried all the top tier gas stations. Switched back to a paper air filter. Grounded the engine. Hooked up the FPR to the BPV/BOV hose. Preformed the .16 cent BPV mod. Smoke tested multiple times. Countless hours testing a researching. Thought about selling the car, alot. This issue has been present for at least the last 5 years. RESULTS What has and hasn't worked for you: All of the above has not worked. WHAT WORKED!?: 2 O-RINGS ON THE FUEL PUMP OUTLET SNOUT. Attached is a picture of how, not only my fuel pump's o-ring setup was, but how I have found them set up in virgin stock fuel pump assemblies . My problem was due to the oring having the ability to become crooked/slanted and allow fuel to pass by. After installing the second o-ring, the seals now sit flush, allowing proper compression 360° around. After this, my ECM was trying to remove a bunch of fuel at multiple load points due to being tuned with this issue present at the time and the fuel pump having 3 different duty cycles. If you have a surge issue that you can't figure out, try this. Even if your stock.