MAF sensor readings?

Tiny
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Thought these might be relevant. Evap System Vapor
Pressure(Pa)-0.587 and Commanded Evaporative
Purge(%)29.4, these are both at idle, will physically test the purge valve this weekend.
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Friday, April 11th, 2025 AT 7:05 PM
Tiny
STEVE W.
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Those show atmospheric pressure. If that tool has an EVAP active test you can close and open the vent and purge valves. That would allow you to test the valve without any extra work. What I'm wondering is if it's pulling vapor in. If it has the test process, you could open and close the valve with it at idle and see what changes.
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Saturday, April 12th, 2025 AT 3:13 AM
Tiny
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Will see if this one has that function, it's not a higher end reader though.
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Saturday, April 12th, 2025 AT 4:31 AM
Tiny
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Was going to test it by pulling the canister hose but the valve is not easily reached.
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Saturday, April 12th, 2025 AT 4:33 AM
Tiny
STEVE W.
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That test would work but the valve isn't easy to access.
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Saturday, April 12th, 2025 AT 2:06 PM
Tiny
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Valve checks out, also checked for intake leaks, couldn't really find anything there. But I did notice something today, my exhaust is vibrating quite a bit and kind of sounds like a softish dog growl. If there is restriction in the exhaust airflow, could this possibly cause a rich condition to occur?
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Monday, April 14th, 2025 AT 10:57 AM
Tiny
STEVE W.
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It could but running rough still sounds like a fuel issue.
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Monday, April 14th, 2025 AT 11:04 AM
Tiny
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Update. Just for the heck of it, I replaced the crankshaft and camshaft position sensors, ltft is now sitting around 0 but short term goes as high as -19 to -23 at idle and if I gradually press the gas pedal it will go to between -3 to -7.
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Wednesday, April 23rd, 2025 AT 9:01 AM
Tiny
STEVE W.
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Sounds like it is still trying to remove fuel at idle but as soon as you open the throttle it stops. So, under vacuum it thinks it's still running rich and as soon as the throttle opens it starts regulating properly. That won't be those sensors, it would be injectors flowing fuel or poor fuel pressure regulation. Get a pressure gauge and check the actual fuel pressure at the fuel rail. I would also pull the plugs and inspect them. It could have a misfire that isn't setting a code that is causing this. I would inspect the plugs for any cracks and the coils as well.
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Wednesday, April 23rd, 2025 AT 4:40 PM
Tiny
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The stft did level out after some driving, I checked the plugs, they looked like just normal wear on them, but it's been about 6 months since the last change, so I am likely to do that soon. Have not checked the coil yet.
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Wednesday, April 23rd, 2025 AT 7:02 PM
Tiny
STEVE W.
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What you want in both LT and ST fuel trims are close to zero, a couple percent either way is normal, but that should be from idle all the way to redline.
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Wednesday, April 23rd, 2025 AT 7:38 PM
Tiny
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Changed plugs and air filter, cleaned the filter housing, and coil pack checked out good. Took car on approximately a 40-mile drive, seems to run decently, rechecked the trims when I got home, long term is now running -8.7 average short term about 5 to 6, I know this still is not ideally where it needs to be, but definitely an improvement over where it's been.
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Thursday, April 24th, 2025 AT 11:16 AM
Tiny
STEVE W.
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Okay, if it's pulling 8% but adding 6 that would give you an overall of 2% which is fine for an older vehicle.
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Thursday, April 24th, 2025 AT 11:35 AM
Tiny
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Well that makes me feel even better about it. Thank you so much for helping with this and being patient with me.
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Thursday, April 24th, 2025 AT 2:10 PM
Tiny
STEVE W.
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No problem. I might even suggest taking it out and driving it like you stole it. Then see if it gets better.
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Thursday, April 24th, 2025 AT 7:23 PM
Tiny
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That is easily the best troubleshooting tip I have heard in a long time lol, and I am all for giving it a go.
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Thursday, April 24th, 2025 AT 7:58 PM
Tiny
STEVE W.
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It's at least a fun one.
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Friday, April 25th, 2025 AT 4:00 PM

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