The check engine light came on, took it to the dealer, and they wanted to start checking valves and cleaning fuel injectors for $700 (no guarantee of success). Here's what I know:

1. The engine light comes on at 3/4 tank and goes off at circa 1/4 tank
2. Gas cap is securely on
3. Premium gas makes no difference to the pattern
4. When engine light comes on consistently get the P0171 code (lean). Once got a P0400 (EGR valve) code, but only once. Codes disappear when engine light goes off at about 1/4 tank.

I just don't see how this could have anything to do with clogged fuel injectors. From other posts perhaps I should try changing the gas cap - but certainly looks and sounds fine when it clicks on.

Any suggestions or narrowing down. Vaccum leak? On other forums it looks like it's much more common to have the light go on at 1/4, and go off at 3/4. Exactly the reverse of what I'm seeing.

Thanks!

My wife has mentioned she's had a couple of instances where the brakes seemed non-responsive for a moment - which from the forums sounds like a potential vacuum leak issue. Could all of this be tied together?

 

I also got the PO171 (running too lean) and dealer said it was debris stuck in mass air flow sensor. Dealer said they cleaned the debris from the sensor and code was gone. I drove for 24 hours and all the dashboard lights came back on. Brought it back to the dealer who said it was a new code that came up (they did not tell me which code) and that I now need to replace the four fuel injectors and injector parts which will run me about $1150.00. For me the engine lights (5 of them) have been staying on anywhere from 2 to 7 days. Then they will go off for between half and a full day before they come back on again. This has been happening for about 9 months and I am only now having it checked because I did not want to hear how much it would cost expecting it would might be expensive and the car was running well. I do not notice the lights going on when the gas tank is a certain amount full or empty. It can happen any time. Thank you for your post and hopefully someone has more insight into this problem we are having.

 

Yes, I have no desire to give the deal an open license to fix the 20 things it MIGHT be. Although having 5 lights come on would be alarming!

Mark

 

Check where the airbox meets the engine. My intake was loose from the engine and pulling in excess air. Had the same intermittent CEL.

 

Are there any other dealers / garages around that you could visit? You have to get some more ideas / bids on any fix.

I've been on the other side (boats) and would always go "big" and hope I could get it done for less but time = money and mechanics deserve their dough if they do a good job.

 

Our intermittent P0171 code has continued, and it is truly intermittent. If I turn the code off it generally stays off for quite a while, at some point pops back on.

I'm starting to suspect it is tied to a vacuum problem with the brake system. We're going to replace the vacuum hose to try and fix increasingly non-responsive brakes. I wouldn't be at all surprised if that solves the P0171 code, as some folks have documented in other web posts.

 

If the Mass Airflow is clean maybe have a tech see what the short trim is doing - I had a similar issue on my 2011 subaru forester and it turned out the Air/Fuel sensor was bad problem from PCV leak I had earlier.

Checking vacuum leaks is a good start!

Good luck and post the solution