Need advice:P0171, P0174 codes appeared today

[pjac5vette]

Hi!! Looking for advice on how to handle the appearance of two PCM codes that appeared earlier this week. P0171 H C and P0174 H C. I reset the DIC and they returned but it has been inconsistent until the past few days.:banghead: The check engine light comes on at different times but stays on until I clear the codes. Some days It comes on as I back out of the driveway. Sometimes it doesn't come on until I drive about 10blocks. The people at Autozone tell me it's the Mass air flow sensor. I trust those on the forum since you are corvette people and now these C5's best so I turn to you for advice. Thanks in advance, clearwater vetteman:dancer01:

 

[JIM KILL]

Codes

You're running lean on both banks - sometimes people get these codes with an aftermarked MAF - assuming your stock here's a few things to check out:

1. Exhaust leaks
2. Precat 02 sensors secure
3. Vacuum leak
4. Intake air leak

I'd also make sure the MAF connection is good and the MAF itself is clean.

I am sure the gang here will have other suggestions.

Jim

 

[zzzona]

P0171 and P0174 are both lean codes. Low fuel pressure can certainly cause this as would be the case with a clogged fuel filter. Aftermarket intakes are also a common cause of these codes. The MAF sensor not being completely seated to the intake to the throttle body. The PCM will NOT know the exact amount of air, and will in turn put in less fuel, because it sees less air.
Make absolutely sure that the MAF is connected correctly, and that your air filter is clean...I also think an air leak around the throttle body may cause it. I also throw these codes on occasion but I can go months before they pop back up. I have headers, intake hi-flow cats, tune....

 

[pjac5vette]

maf codes

Thanks for the response. I am going to check the setup and make sure the clamps are tight on the maf and the throttle body. I also saw maf cleaner on the napa site. I went to a car wash last weekend and spayed the vette with the clearcoat and some other sealer that came out like bluish foam. I noticed that on the air filter yesterday and changed that last night but still got the codes on the way home, Thanks again and I'll update you on my progress:dancer01:

 

[pjac5vette]

still getting p0171 & p0174

Well I checked my connections for the Mass Airflow sensor and they are all tight connections. I relocated the remote air intake air temp sensor to the stock sensor and still get the check engine light and the following codes. P0171, P0174, C1243, U1096, U1016.:banghead: Idle is not as smooth as usually was before the check engine light came on weeks ago.
Tonight I picked up some Mass air flow sensor cleaner and took off the unit and cleaned it with the stuff, reassembled the unit and made sure the connections to the air coupler are tight. vette started fine but still has a slightly rough idle that only a car nut like me would notice.:lmao: Will find out in the am if the check engine light reappears. Appreciate any ideas from the corvette world. I try to trouble shoot stuff my self but might have to leave this to Vern, Thanks again:dancer01:

 

[RevXtreme 1]

Bring it in....we will scan it for free (with a state of the art scanner that gives a ton more info than the autoparts guy's) and help you out.:thumbsup:

 

[pjac5vette]

codes P0171,P0174

Thanks for the free diagnostic check!!:dancer01: That will be a great help to me. What are your hours of operation and do I need to make an appointment? Thanks again, Phil:thumbsup:

 

[RevXtreme 1]

Mon-Fri 9-6, Sat 10-3 (or later if needed).:thumbsup:

 

[pjac5vette]

Hi guys, "Thier Back"!! I'v been busy since my last visit when you cleaned the fuel injectors. That solved the code problem for a few days but they came back. I don't think we replaced the fuel filter/ Anyway the lean bank codes keep popping up and not always the left and right. Sometimes I only get p0171 HC and sometimes p0174 HC and sometimes both. Also getting U1160 HC, B0361 HC, B0441 HC, B0446 HC, Thanks for any advice