P0171 & p0174
Thread Starter
Instructor
Joined: Jun 2011
Posts: 165
Likes: 3
From: Cave Springs Arkansas
P0171 & p0174
Fuel trim system lean bank 1 & 2.
2001 coupe, a4, 100k miles, pretty much stock under the hood. Swiss cheesed intake (did idle relearn procedure), new plugs & wires, new fuel filter, cleaned MAF sensor, techron fuel treatment, still intermittent check engine light. Not throwing any DIC codes.
Check engine light started coming & going intermittently a few months ago. That's when I started replacing stuff that I knew needed replacing anyway (plugs, wires, fuel filter).
Started with p0171, but since it's now p0174 also, I don't think its o2 sensor, unless it's 2 or more of them.
Any suggestions????
Thx
2001 coupe, a4, 100k miles, pretty much stock under the hood. Swiss cheesed intake (did idle relearn procedure), new plugs & wires, new fuel filter, cleaned MAF sensor, techron fuel treatment, still intermittent check engine light. Not throwing any DIC codes.
Check engine light started coming & going intermittently a few months ago. That's when I started replacing stuff that I knew needed replacing anyway (plugs, wires, fuel filter).
Started with p0171, but since it's now p0174 also, I don't think its o2 sensor, unless it's 2 or more of them.
Any suggestions????
Thx
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
Fuel trim system lean bank 1 & 2.
2001 coupe, a4, 100k miles, pretty much stock under the hood. Swiss cheesed intake (did idle relearn procedure), new plugs & wires, new fuel filter, cleaned MAF sensor, techron fuel treatment, still intermittent check engine light. Not throwing any DIC codes.
Check engine light started coming & going intermittently a few months ago. That's when I started replacing stuff that I knew needed replacing anyway (plugs, wires, fuel filter).
Started with p0171, but since it's now p0174 also, I don't think its o2 sensor, unless it's 2 or more of them.
Any suggestions????
Thx
2001 coupe, a4, 100k miles, pretty much stock under the hood. Swiss cheesed intake (did idle relearn procedure), new plugs & wires, new fuel filter, cleaned MAF sensor, techron fuel treatment, still intermittent check engine light. Not throwing any DIC codes.
Check engine light started coming & going intermittently a few months ago. That's when I started replacing stuff that I knew needed replacing anyway (plugs, wires, fuel filter).
Started with p0171, but since it's now p0174 also, I don't think its o2 sensor, unless it's 2 or more of them.
Any suggestions????
Thx
Racer
Joined: Apr 2012
Posts: 282
Likes: 4
From: Dayton Ohio
vacuum leaks will cause your codes. Also check your intake to head seals! Use some carb cleaner and spray around the intake while running. You will hear a change in rpm when you spray in the area of the leak! Good luck!
Drifting
Joined: Sep 2009
Posts: 1,719
Likes: 4
From: cinnaminson n.j.
St. Jude Donor '14
If you don't find any vacuum leaks, have the freeze frame data checked. This will tell you the exact contains when the codes set. If its not at idle speed with closed throttle, you probably have a skewed MAF sensor.
