Scottydoggs
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bad o2. or maybe a injector is leaking. but when one of them stick open you see a -22.
Tonyrodz's Tahoe Build Thread
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I wouldn't worry about the fuel trims -- they're not THAT far out, and not far enough to cause what you feel as a miss. Keep your eye on the short term trims and if they start moving to over 8 or 10% either way it will be time to look into them. You can reset the LTFT with your Tech 2 and start them from scratch if they bother you; they are what your STFTs have been doing over (past) time. You never know, maybe they're adjusting to the new muffler and the airflow. New breathing, maybe? Not sure how much different your new muffler is from the old.
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Tonyrodz
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Both mufflers(old and new) are a straight through design, only difference with the new one is it's a little longer. To reset fuel trims, where would that be? Special functions maybe?
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Tonyrodz
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Checked the header bolts real quick and looked it over under the hood for any loose connections, or anything sucking air--nothing visible, everything feels tight. Fuel trims are still off between banks 1 and 2.
97YukonNZ
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Have you thought about getting a plastic drink bottle of water and squirting a bit along the inlet manifold while shes running incase you have a vacuum leak?
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Tonyrodz
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Haven't thought of that. Wouldn't carb or brake cleaner give the same results? If there is a leak what would the water do?
97YukonNZ
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Yeah either of those will work. If their is a leak,i think when you spray either of them it will surge in idle letting you know where.
Water will stop the miss for a second and may show visully where a vac leak is present.
Was just thinking water because of it being free and available now!
How much has it been driven to see if the LTFTs line up better with the STFTs? Your short terms were perfect earlier in the week, and if they stay within +/- 5% they'll affect the LTFTs over time and those will get closer to zero. (Stop living in the past, LOL.) Look elsewhere for your miss.... carb cleaner, brake cleaner, propane, all can be used around the intake to investigate leaks.
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Tonyrodz
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I drove it a few blocks today. My gf drove it twice this week locally and she also noticed it wasn't running right. I can hear the exhaust note from the tailpipe sounds off--if that makes sense. At idle and while driving it.
97YukonNZ
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02 sensors not disconnected or bad contact on 1 side of exhaust?
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Tonyrodz
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Shouldn't be--but we know how that goes. I actually haven't been under the truck since it fell last week. I didn't get any o2 codes, I scanned it today. Used a scanner instead of the Tech 2.
Sparksalot
Elite Member
Fell?
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Tonyrodz
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I had it jacked up last week with a jack stand supporting the ps under the axle tube--also had the jack still under it. Long story short trying to bring it back down, the jack went crooked, jack stand tilted and it got stuck like that. Had a feeling it was gonna fall so I grabbed a rake and tried to pull the jack stand out(because it was stuck sideways)and the truck fell. Had a feeling that was gonna happen. Second time this has ever happened to me. Once was enough.
Sparksalot
Elite Member
Glad it did not smack you on the way down. I had a guy working for me a few years ago that got hit by the frame of his truck in a similar situation. It smacked him hard enough to cause permanent brain injury. He was in the army at the time and ended up medically retired out of it.
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Tonyrodz
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That's pretty sad. I don't mess around when it comes to crawling under a car. I've been paranoid about that since I was a kid.
HiHoeSilver
Away!
We've done some fuel trim interpretation way back in this thread before, I believe.
See what happens to the short terms when you get on the gas?
Sounds like you need a better floor jack and jack stands.
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Tonyrodz
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This Tahoe sux.
They're good, it's where it was that was the problem.
HiHoeSilver
Away!
You know it hears you every time you say that, right? No wonder it doesn't like you anymore.
Sorry if I'm late to the dance here, but when's the last time you reset the trims? The long terms adjust over time to keep the shorts at 0. Is that scan data at idle?
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Tonyrodz
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The 1st scans were just at idle. Unfortunately I wasn't able to get pics of the fuel trims on the short ride today. I did see a high of 10 on the short term trims--I think on bank 1. Driver's side? Do you know how to reset the trims with the Tech 2? I'm guessing it would be under the "Special Functions" menu?
