Jump to content

Search the Community

Showing results for tags 'p0171'.

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • GM-Trucks.com Original News & Product Reviews
    • General Motors Product and Industry News
    • The GM-Trucks.com Garage - Vehicle Testing & Product Reviews
    • The Newsroom Archive
    • The Garage Archive
  • Next-Generation Full Size Speculation - 2026+
    • 2026 Chevrolet Silverado & GMC Sierra
  • Battery Electric Vehicles - 2022-2026 Ultium Platform
    • 2022-2024 GMC HUMMER EV Pickup & SUV
    • 2024 Silverado EV & Sierra EV
  • Fullsize Truck & SUV - 2019-2025 T1XX Platform
    • 2019-2025 Silverado & Sierra
    • 2020-2024 Silverado HD & Sierra HD
    • 2021-2023 Tahoe, Suburban, Yukon, Yukon XL & Escalade
  • Fullsize Truck & SUV - 2014-2019 K2XX Platform
    • 2014 - 2019 Silverado & Sierra
    • 2015-2020 Suburban/Tahoe & Yukon/Yukon Denali
    • 2015-2019 Silverado HD & Sierra HD
  • Fullsize Truck & SUV - 1999-2006 GMT800 & 2007-2013 GMT900 Platforms
    • 1999-2013 Silverado & Sierra 1500
    • 2000-2014 Silverado & Sierra HD
  • Chevy Colorado & GMC Canyon
    • 2023-2024 Chevy Colorado & GMC Canyon
    • 2015-2022 Colorado & Canyon
    • 2005-2012 Chevy Colorado & GMC Canyon
  • Midsize Crossover & SUV
    • 2024 Chevrolet Traverse, GMC Acadia & 2025 Buick Enclave
    • 2017-2023 Traverse, Acadia, Enclave & XT5
    • 2019 - 2024 Blazer
  • Classic Chevrolet / GMC Pickup Trucks
    • 1988-1999 Chevrolet & GMC C/K GMT400 Platform
    • 1973-1987 Chevrolet & GMC Square Body / Rounded Line Pickups
    • 1967-1972 Chevrolet & GMC Glamour / Action Line Pickups
    • 1960-1966 Chevrolet C/K/Apache & GMC 1000-3000 Pickups
    • 1982-2005 Chevrolet S-10/Blazer & GMC S15/Sonoma/Jimmy
    • 1969-1994 Chevrolet K5 Blazer & GMC Fullsize Jimmy
  • Marketplace
    • For Sale/Wanted
    • Member & Vendor Rating Forum
    • Member Product Reviews
  • The Lounge
    • Off-Topic
    • Future Vehicle Speculation & Spy Shots
    • Automotive Industry & Market Discussion
    • New Member Introductions
    • Meetups, Events, & Gatherings
    • GM-Trucks.com Comment Box
  • Hobbies & Lifestyle
    • Photography
    • Major League Sports, Outdoor Recreation, Firearms, Hunting, OHRV
    • Racing, Strip, & Track
    • Trailers, Hitches, & Towing
    • Garage & Home, Snow Plowing, Landscaping, & Lawn Care
    • Technology, Devices, & Gaming
    • Vehicle Buying, Financing, Incentives, & GM Card
    • Vehicle Builds
  • Technical & Advanced
    • Vehicle Appearance, Care, & Maintenance
    • Ask the GM Technician
    • Performance Engine Tuning
    • Transmission, Suspension, Transfer Case, & Axles
    • Wheels, Tires, & TPMS
    • Audio, Electronics, OnStar, MyLink, Intellilink & SiriusXM
    • How-To
  • Commercial Vehicles
    • 1980-2009 Chevrolet Kodiak and GMC Topkick
    • Chevrolet Express & GMC Savana
    • Chevrolet Silverado Chassis Cab 4500HD/5500HD/6500HD
  • Black Truck Club's Topics
  • Texas Owner's Group's Topics
  • California Owner's Group's Topics
  • New England Owner's Group's Topics
  • Midwest Owner's Group's Topics
  • South Carolina Silverado Owners's Topics
  • Canadian Owners Club's Topics
  • SCUBA divers of GM-Trucks's Scuba Talk
  • Red Truck Club's Topics
  • Idaho Sierra & Silverado Owners Club's Idaho
  • Colorado Trucks's Exhaust Setups
  • Colorado Trucks's Pics of trucks
  • SEO Paint's seo color ordered
  • NorthSky Blue Club's NorthSky Blue Metallic
  • NorthSky Blue Club's Pics
  • diesel 3.0's Topics


  • Events
  • Birthdays
  • Texas Owner's Group's Events
  • California Owner's Group's Events
  • Midwest Owner's Group's Events
  • Red Truck Club's Events


  • Articles
  • News
  • Reviews
    • Project Sierra
  • Resources


There are no results to display.

There are no results to display.

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start




Website URL









Found 4 results

  1. Please see attached file for report. Been dealing with this for a while. Mechanics said they smoke tested and found no leaks. Fuel pressure tested at 58. Has random misfire code p0300 and lean code p0171. Has installed new, Delco cap and Delco rotor and Delco Iridium plugs. Last year tried Bosch plugs and new after market cap and rotor. Still no difference. Shows classic sign of vacuum leak as throttle increase causes fuel trims start to lower. What do you think? SavannaReport08062022_0001.pdf
  2. Hello. I have a Silverado 1500 4.8L base model with 200K miles. I could use some guidance on how to troubleshoot two engine codes that my truck has. P0101 and P0171. I erased the codes, unfortunately. This is what I have done thus far: -Inspected the Air filter (it is clean) - Cleaned the MAF sensor with MAF cleaner. - The MAF values are responsive to changes in engine RPM. I don't have any special tools to check for vacuum leaks. I Took live readings with my Zurich ZR8 code reader The LTFT1 and LTFT2 hover around +14% when engine warm and idling around 600 RPM. Drove around a little and LTFT1 and 2 rose as high as 21%. MAP - 11 Hg MAF reads 0.52 lb/min TPS reads 9% Update 9/5/2021: I tested the fuel pressure and it is in the normal range, 58 while idling, a bit lower with the key in the "On" position. While running the engine, In short bursts, I sprayed brake cleaner around the air intake hoses and gasket and listened for changes in the idle pitch. Admittmedly, I may not have hit every crevice while doing this. No leaks detected. What are my next steps?
  3. Hello, I have a Chevy Trailblazer 2007 LT 4wd high miles, I have a P0171 and I've been trying so hard to figure it out without going to a repair shop. The Frame freeze data show a P0171 recorded at Coolant temp 206, Idle RPM , LT Fuel trim 26%, the Oxygen sensor and the MAF readings appear normal to me. Live Data now is showing LT 29% on idle numbers improve to below 10% if increase RPM even slightly and get worst very quick on IDLE. I also noticed RPM isn't 100% stable on idle but nothing major. Sometimes the check engine light will suddenly go away to come back later, I also notice a gas cap light on from time to time if that matters I already cleaned Throttle body, MAF , my Air filter was recently replaced. I visually double checked all the air hoses no obvious crack, Breathing cap was cracked so i replaced it but nothing changed. I tried a water test on the manifold gasket but the engine isn't shivering when I toss water, I don't have access to a smoke machine. I can hear a little whistling from the manifold but I'm not sure. couple days ago I had the Throttle body control error but it cleared when I cleaned it and it never came back. Another test of pressing the brakes on Live date show a huge increase in Short term fuel trim to 32.5%. Please help me because The car isn't worth spending thousands on it and it might not even work, is there anything else I can try, is it possible Fuel pump or fuel filter? Thank you so much
  4. If anyone knows of a previous thread that explains similar symptoms please let me know, I haven't been able to find any. I have been getting a CEL for p0171(lean bank one), p0405 (egr), p0449 (evap vent seloniod), and occasionally p0174 (lean bank two), and p0430 (cat system efficiency below threshold). It makes sense that all of these codes could come together so let me explain a little bit of what's going on. I bought the truck last fall with about 200k miles, and unfortunately had to have the trans rebuilt so I am trying to avoid throwing parts at it and hoping it fixes the issues. When I bought the truck there was a code for the evap vent seloniod, which as far as I know would more than likely just make it so that the gasses can't excape when fueling and casuse me to have to hold the handle so I haven't been in a huge rush to replace that. There were exhaust manifold bolts broken in the block so I decided to put shorties on while everything was apart since they were relatively inexpensive, but these didn't have the port for egr and I bought the egr block. When swapping the manifolds, I found out the collector on my y pipe was cracked and plan to drop that down and weld it up when it gets warmer out. So I expect those two codes. As far as the cat efficiency being off, that has only came up a couple of times and I haven't quite gotten a chance to figure out anything that happens consistently before that. When it was real cold my truck would somewhat surge when stopping at stoplights. Now the bank one too lean code is the one that concerns me the most. For some reason the bank two lean isn't as common, and is usually just a pending fault and not a current fault like the bank one is. I thought maybe the lean codes could be from the known exhaust leak but that seems inconsistent with the bank having most trouble. Monitoring my fuel trims using torque pro I found that my long terms were pegged at 25 and the short terms were even higher. The short terms dropped when I revved the engine up to around 2500 and I could hear a slight Rev when spraying the intake with brake cleaner. This was on the passenger side, near where the egr was. It was close to the throttle body, and a new gasket was super cheap so I decided to clean the throttle body and clean the gasket which didn't do much if anything for me. Everything I came across looking at fuel trims led to vacuum leak, so I thought maybe the maf was bad so I tried a new one which didn't change anything either. I put the old one back in and removed the egr block flipped the o-ring around and that seemed to help for a day or so. But it came right back to where it was prior, so thinking it could also be a fuel issues I checked the pressure with a loaner from oriley's. Originally the key off pressure was up near 55 psi, the I turned the engine over and the pressure was around 45. After revving it was around that range still. I let the pressure off the tester and turned the key back on and this time the pressure was getting up to about 30 and then coming to about 25 after starting The gauge could have bad calibration, or I could have a fuel delivery issue. Anyways I have not noticed any misfires, nor have I gotten any misfire codes. My fuel trims remain high at idle (ltft 25%, stft from - 3% to around +10%), and lower when under load, especially if I'm actually driving. I was assuming that if it was a fuel issue I would see the fuel trim higher under load and more normal when idling? Any suggestions as to what else I could do to try to narrow this down and avoid taking it into the shop? Sorry for the wall of text, but I wanted to explain the best I could as this doesn't quite seem to be making sense.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.