Surging

Hey not sure how to describe this issue when im between about 2500 and 3500 rpm im getting a kind of surging feel mostly happens in 3rd or 4th gear on inclines it goes away if i drive a bit more aggressive or bit more grandpaish. Have not had any cel or new noises with this sudden change but my fuel mileage seems to have dropped a bit. Any ideas of things that i can start checking would be very helpful

If you have live data, monitoring your boost level may help clarify. I would also check for vacuum leaks.

Any pending codes?

Any mods? What kind of tune do you have?

Ok well i think i figured it out. Went to fill up gas and caught new guy at station starting to put in regular instead of super he is also the one that pumped my gas at last fill I've only ever put super in so after a fill of super the issue seems to have gone away. Crazy how much different my car runs on that crap

What kind of tune do you have?

Dont know i would assume stock. the only thing that has been done under the hood is a cobb cai although it does seem a bit quicker than other stock ones I've driven before i bought this one

Running an aftermarket intake with a stock tune is a great way to kill your engine. There's a reason Cobb provides a tune for their intake.

From what you've described, you may have a 91 octane tune already, so running low octane gas messed you up. Did the engine rattle under load?

If possible, find out the tuing situation from the PO. If not, get an AP and take control of the situation. Are you SURE the intake is the only mod?

If you have live data, monitoring your boost level may help clarify.

 

Wireless OBD2 plug and torque app through your smart phone can get you live data for about $20. that's just for something to refer to while you wait for the accessport.

 

I called Cobb about the stage 1 SF setup a long time ago, even Tech support wasn't confident in their map with this intake. The guy actually suggested further tuning. I've read a few threads on here with members bashing the SF intake.

If it does have a tune i dont know what it is everything that was done to the car was done by po. I got car from a dealer and they had no info about anything. There was no rattling or pinging when the issue was happening just huge loss of power and surging on inclines

I interpret surging as a sudden spike upwards in RPM and falling off, repeat once more before redline. Are you familiar with fuel cut and how it relates to the turbo legacy? Might be worth researching on the side. Unfortunately, in the process of "returning to stock" people will unmarry their accessport and it's respective tune is pulled off the ECU. In your case, it's possible. On the other hand, you could have a bunk tune and the accessport is still married to the car, but not in your hand ie; lost, stolen, sold. I don't know enough about OS tuning. Someone help this guy figure out how to check the tune.

Ya thats fairly close although it drops off then spikes up. Watching the tach it was barely noticeable. My budget is pretty tight right now so an ap is out of the question till at least mid summer. If there is any other way to check to see what tune it has im all ears

Bummer. It appears you might have to use the Google Try to find a stock intake system at a salvage yard. It won't be hard to find, The PNW is littered with Subaru parts.