So my 2016 200T has been acting weird the past few weeks and I ended up with a check engine light yesterday. The car would hesitate in the 4-5k rev range with my foot on the gas and I would hear some burbling/backfiring while I was still pressing the gas. I scanned the codes and it came back with P0171 System Too Lean (Bank 1) and P1170 Fuel Performance/Port Injector. From what I was able to find online it seems like it could be a vacuum leak issue but the person who scanned the codes said it could be a injector or fuel pump problem. My car is tuned if that makes any difference.

What are some things I can check to identify the problem? What would be the most common areas that can be causing a vacuum leak on these engines?

 

Try spraying the vac lines with some brake cleaner while the car is idling. If the idle changes while you're spraying into an area, you have discovered where a leak could have come from.

 

Most likely the issue is the PCV Hose. Its where the crankcase vents back into the intake pipe. When that comes loose it throws those exact codes.

 

Unfortunately that’s not the issue and I haven’t figured it out yet. The CEL was cleared by a shop and hasn’t come back since but the car is still really sluggish and has the same symptoms. I’ve also noticed engine oil at the top of the engine and near the turbo muffler / charge pipe. Still trying to find a trustworthy shop to diagnose and repair the issue.

 

Those symptoms almost certify that it is a PCV Hose. PCV stands for positive crank ventilation, literally the crankcase of the motor vents pressure through it, back into the intake. Oil comes up with it, which is why people put oil catch cans inline to this.

Another idea, being you have the 4cyl turbo, is the boost regulator/wastegate. These are known for going bad on the 200t/300's, but wouldn't result in oil being on the top of the engine.

 

Here's a breakdown of the codes:

I would definitely check to see where that oil is coming from.

 

So I just checked again and the hoses are all plugged in and are not loose. I did replace the regulator about 4k miles ago (third time). It seems like the oil is coming from underneath the valve cover but I can’t tell exactly because theres also oil on the turbo muffler. Do you think it could be the valve cover gasket? I took some pics but its sorta difficult to tell in pictures

 

Any chance that was just oil that was spilled when filling the engine after an oil change?
Just based on the pics i would consider that sweating more than a leak...but i realize it may appear as more in person.

 

hard to tell but I don’t think so because I got the CEL and the drivability issues before I got an oil change. When I first noticed the oil after getting the CEL there was considerably more and it was still wet. I got an oil change after that and they cleared the CEL and added fuel injector cleaner. Its been a while now and the CEL hasn’t come back and the oil has definitely dried compared to before. The car still feels sluggish and it loses power briefly in the upper RPM range with some backfires if I’m going WOT

 

Are you able to flash it back to stock to eliminate the tune being the issue?
Your description above really sounds like a boost regulator...even though you just replaced it. I know that sounds unlikely.

Also that second code is basically telling you that even though you have a lean condition, the direct injectors are supplying a normal amount of fuel.
Where in reality if the car was running lean, the direct injectors should be supplying the max amount of fuel...in an attempt to correct the lean condition, before the code finally triggers the CEL.

 

Yes, I’ve already flashed back to stock after we cleared the CEL and added fuel injector cleaner. Initially the car started having the issue with the hesitation and exhaust backfiring for about 2 weeks until it threw a CEL. I put the stock intake back on and flashed back to stock and it doesn't do it as severely as before but its definitely still there. I don’t think its the regulator because every time I’ve had to replace it before it was a different kind of hesitation than what im currently experiencing. The regulator going bad also never caused back fires before. Seems like the sound of the car has changed too, it sounds like extra air or rasp is being pulled if that makes any sense.

I’ve taken it to 2 shops so far and one told me not to worry about it and the other said it could be a turbo oil leak even though theres no oil around the turbo anywhere

 

how many miles are on it? It may be worth it to swap back to stock and take it to the dealer if it's under warranty. And if not, as a last resort, you can always have them diagnose the issue and then fix it yourself. I previously owned an 06 WRX for 2 years, I had this issue a few times. The main things you want to check are:Vacuum/Boost leak( at idle keep an eye on the boost gauge if you have an F-Sport. If its fluctuating with no load on the engine, AC off then it points to a vacuum leak, Also keep any eye on it during full boost and see if its holding the boost all the way through. Its normal to taper down a bit after hitting full boost). Also check spark plugs, air filter, make sure all hoses are tight and there are no cracks. Since you have the turbo muffler, also make sure all connections there are fine, including the recirculating valve. Another thing to do is run a fuel injection cleaner service to clear up any clogs/gunk in the injectors