Adamj

Hey guys I'm extremely new to the Audi world. I just bought a 2008 Audi a4 2.0 fsi with 111,000 miles. It's an automatic. I don't know much about cars so I had an AFE air intake installed by a mechanic. About two days after he put it on it started throwing p0171. I took it back in and he said he double checked the air intake and put a new crank case vent valve on it (for free) and said that was the problem. Well I just got back up the mountain and the light is on again for the same problem. Also my car feels slow as crap. He said it was boosting 11-12psi when he drove it with the computer but I just don't believe it. I also put on the GFB diverter valve as I heard those can effect boost. Do y'all have any idea what could be causing it to throw his code? Thanks a to

Dolamite

Things like air intake and diverted valves have little impact on performance. Once you start modding you're altering the engine there's no way around it and you should expect codes. If you want performance the best way is a tune and even then you're compromising the reliability and life of the engine. Of you think it can go long with a stage tune, then it can always go longer without one. It's the nature of the game. Subtle changes can have profound effects. Stay away from the gimmicky Bolt-ons that promise you this and that, it's common sense. If you're bent on performance then try stage 1 then a test pipe or hiflow cat stage two. These cars are not strip cars; realistically your may get a 13+ car. Don't know how long you want to keep it, but u need to ask yourself if it's worth it chasing boost.

Adamj

Ok thanks, do you know what would cause it to have that code?

Dolamite

Did you pull the code yourself the first time? Was there an identical code pulled the second time with the cel? I'd check for vacume leak since you just messed with the intake. PCV or MAF sensor are possibilities, but I doubt it since you would've gotten a code before you put on the intake unless either suddenly went south. How long have you owned your car? The aftermarket diverter valve shouldn't be the issue, unless you're getting boost codes. You probably don't have one, but you need a vag cable($350), but a must have if you want to keep your car long and not have to pay to get it diagnosed every time. If you have access to one you could check you fuel trims which would give you more feedback to pinpoint off. When you start modifying your engine you add another variable to problems that arise. Like I said, if you care then you NEED a ross-tech cable, kinda leaves you blind in these situations. There are some codes that regular obII scanners will not pick up.

Tony Zamudio

srry 2 bring up old dead post but just recently installed afe intake and same code along with Lost of power any ideas on fixes

Hayabusafalcon

Ditch the aftermarket intake. Those things don't do much anyway. There is nothing wrong with the stock intake system. Good luck, Haya....