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Showing results for tags 'P0171'.
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p0300 2002 GMC Savana 3/4 ton 5.7L Gas p0300 random misfire
smitty123 posted a question in Ask the GM Technician
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 -
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? -
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
