2004 Stock LS1 P0171 code help
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2004 Stock LS1 P0171 code help OK, it`s stock except for K&N intake, gets P0171 code, Banks 1&2 SRTM`s are good (moving positive and negative @ 5 % idling), plug coil packs all good, O2 sensors good, new PCV, MAF sensor, Sprayed soapy water & brake cleaner around every hose, fitting, intake gasket with no change in idle. Miss seems to more noticeable as it warms up. Holding @ 200rpm miss is highly noticeable. Also pulled electrical connections off on each fuel injector at idle trying locate miss, but nothing found. Any help appreciated. 43k miles on engine.
Pull your injector clips when it's misfiring harder. You said it misfires very noticeably if you hold the idle up, so try it there not when it's barely misfiring at idle.
If it's an auto put it in gear and hold the rpm up, that should make the misfire more severe and easier to find too.
It's going lean at some point for sure though if you get a p0171 code, you'll need to watch fuel trims from a cold start all the way to warm and under load too and accelerating. When you find where it goes lean you'll be able to figure out why.
Also, I see quite a few threads where guys with old LS motors with low miles end up having bad valve springs. A lot of years with low miles is always an indicator the motor has done a lot of sitting with pressure on the springs and that's a bad combo.
If it's an auto put it in gear and hold the rpm up, that should make the misfire more severe and easier to find too.
It's going lean at some point for sure though if you get a p0171 code, you'll need to watch fuel trims from a cold start all the way to warm and under load too and accelerating. When you find where it goes lean you'll be able to figure out why.
Also, I see quite a few threads where guys with old LS motors with low miles end up having bad valve springs. A lot of years with low miles is always an indicator the motor has done a lot of sitting with pressure on the springs and that's a bad combo.
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Pulled injector clips at cold, warmed up at high idle & loaded in park. Misfire didn`t change. Still p0171 code. sprayed brake cleaner all over at high idle , no change. Short term trims still good except bank 1 shot up to +50 % for 15 secs, then recovered to normal !! Bank 2 normal all the time. Any suggestions ?
Have you watched the 02 sensor in the data stream to see if it seems funny? Hell try a new one if you're not sure.
Spray brake clean at low idle, not high idle, at low idle there is more vacuum in the manifold and will be more likely to pull in whatever you are spraying.
Did you spray the injector o rings at the manifold? Seen those leak before.
Check all of your PCV hose closely, they rot and go to ****.
Spray brake clean at low idle, not high idle, at low idle there is more vacuum in the manifold and will be more likely to pull in whatever you are spraying.
Did you spray the injector o rings at the manifold? Seen those leak before.
Check all of your PCV hose closely, they rot and go to ****.
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New O2 sensor for bank 1 exhaust. Sprayed all at low idle also. Took of every vacuum hose , inspected carefully then resprayed hoses at low idle. Didn`t intensely spray around injector o rings , but will try. Last time driven had loud backfire, never did it agn. Tks
Take a peek at those valve springs.
Backfire is something firing out of time, doubt the cam jumped and ignition components going whacko at random isn't common. However from time to time people post about crank sensors getting funny and causing some of these issues.
Not sure how the P0171 plays into it all yet, hard to say over the internet and not being there.
You mentioned stft was good, what about LTFT, LT must be off if it's setting a code.
Also, I can't figure why you have a misfire but it doesn't change when you pull injector connectors, have you tried it in gear at high idle?
Backfire is something firing out of time, doubt the cam jumped and ignition components going whacko at random isn't common. However from time to time people post about crank sensors getting funny and causing some of these issues.
Not sure how the P0171 plays into it all yet, hard to say over the internet and not being there.
You mentioned stft was good, what about LTFT, LT must be off if it's setting a code.
Also, I can't figure why you have a misfire but it doesn't change when you pull injector connectors, have you tried it in gear at high idle?
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Will look agn at LTFT & spray injector seals at hi idle for sure. Pulled injector connectors at high idle = similar change on each cylinder. Also pulled coil pack connectors with similar change each cylinder. Heavy smell of gas when running. Don`t want to crack into valve springs just yet. Miss at idle not that noticeable until warmup usually.
