LS1ECHO

Hi guys new here kinda lets just say its been a while, hows it going? So i have a 98 camaro ss i do have a lean code p0171. Just checking everything out to narrow it down. Though im more familiar with lt1s, not so much with my ls yet. What is the average kpa idle reading for map on ls1. Mine was idleing around 33kpa off the laptop and innova scanner. Also if someone could tell me what other average readings are for MAF, and o2s. Just checked my fuel pressure as well. Its 50psi with key on, about 60psi running. The car runs good just kinda thought something was off and then it threw that code. Thanks guys. You guys were a huge help with my caprice a year back. I mean huge help. I added a few pictures of freeze frame's.

1 FMF

iTrader: (1)

your 10 inhg manifold pressure is equivalent to 20" vacuum, which is what you would expect for a healthy engine idling well with a not wildly inaccurate a/f ratio or incorrect ignition timing, bad rings or bad valve seats, etc. And it was at 600 rpm as well, if you idle up to 1000 to 1500 rpm and the manifold pressure drops down around 7-8 which would be around 22" vacuum then that tends to indicate everything is healthy.
fyi- atmosphere pressure is 30" inhg, or 101 kpa, so when you only see 10 inhg manifold pressure then thats 30-10 = 20inhg vacuum... which is what i am accustomed to playing with carburetors.

your p0171 is a lean condition that happened and existed for longer than a set period of time, might be something like 2 minutes i'd have to look it up. but if everything else seems 100% no engine bucking, surging, stalling and just the light on your dash, then cause is usually 1 or 2 things:

your maf sensor is giving an incorrect reading for certain airflow ranges, not enough to cause performance problems but enough to trip a DTC. a $100 for new MAF, and a flat blade screw, driver might fix the problem.

you have unmetered air entering the intake manifold, which is not being measured by the MAF sensor. and this can be happening periodically, not all the time, and tripping p0171. actually it's unmeterd air eventually being sensed by the o2 sensors, and reporting a lean condition, common causes are solenoid valves that don't seal and leak air, these can be on the AIR pump and on the EVAP system. These solenoids work electrically, but their valves over time get worn and when closed they don't seal, and they can be very hard to diagnose and find because under certain conditions they will seal then sometimes they don't. best case scenario for these is you have other DTC's indicating a problem with that system- the air pump, evap solenoids, etc. otherwise it's replace the parts and hope you got it.

when i got my 2006 truck i was getting period p0171, but also got p0101 which is MAF out of range. previous owner had k&n sucking from wheel well and I could see water and dirt stains within the MAF. so that was easier to decide to spend $100 on a new MAF (and stock airbox + paper filter) and i never got another p0171, p0174, or p0101 again. if you have an aftermarket air lid, oiled k&n filter, or live/drive in dusty dirty conditions then i would lean towards a new MAF.

RPM WS6

iTrader: (3)

I agree with the MAF being a possible cause, but I disagree with replacement as a first course of action for this piece. It doesn't seem that the MAF has failed at all, so a cleaning should be the first order of business. They can be disassembled (4 torx bits to remove the ends from the center section) and the exposed wires of the center element thoroughly cleaned of any oily residue (which is a very typical problem if a K&N style filter was ever used, as mentioned above.) Sometimes a simple MAF spray cleaner is not enough to get the job done, my preferred method is Q-tips and rubbing alcohol. You have to be very careful to not apply any pressure to those wires when cleaning, just let the alcohol soaked Q-tip glide along their surface to restore a bright silver color and remove residue. This has worked to solve minor driveability issues that many folks have seen over the years.

I would also suggest checking fuel pressure under load. You mentioned ~60psi running, which is great, but sometimes pressure will drop under load causing issues that won't show up during an idle or free-rev test. If you can get a gauge with a long enough hose, you can run it out the rear of the engine bay and tape it to the windshield, then get some readings under load.

Since this code is bank specific (Bank 1, driver's side), and you're not getting any codes for Bank 2, this could indicate some sort of vacuum leak or fuel system issue which is specific to only that one side (such as an intake gasket leak, exhaust leak near the O2 sensor, AIR system issue as mentioned above, or even a fuel injector issue on that bank), but in this case I see that LTFTs are highly elevated on both banks (at +24%; they really shouldn't be any higher than about +10% for a stock tune/stock engine) even though you're only getting that one DTC. Since these elevated readings are present on both banks and are equal, I'd focus my initial attention on macro possibilities that could cause a universal issue rather than any bank specific diagnostics at this point. Again, I'd want to look at fuel pressure under load and make sure that the MAF is totally clean.

I also noticed that you have some readiness monitors that are not completed, specifically the O2 heater test and EVAP. Have you recently reset the PCM or disconnected the battery? EVAP sometimes takes a while to run, but the O2 heater test should run after the first or second cold start. If it's been incomplete for a long time, then something else might be amiss.

LS1ECHO

update - thanks for the awesome responses guys, it ended up being broken pcv hose in a few spots i couldnt see. I repaired that and the ltft and stft both are around 0. Mostly like -8 - 8 ish it fluctuates. I have driven her in a while to really make sure all is good but it seems good for now. Il update if anything else pops up. And the maf seems to be fine but theres something suspicious about it. It was very dirty and i cleaned it. Out of the 3 little wire sensor parts in it 2 are silver and 1 is orange like its rusted odd enough.