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Showing results for tags 'P0171'.
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
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.