Fuel Trim Lean-
Thread Starter
Staging Lane
Joined: Aug 2006
Posts: 53
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Fuel Trim Lean- Have 2 codes being thrown. SES light turns off randomly and stays off for a day or 2. Codes are: P0171: Fuel Trim, Bank 1, system too lean. And P0174 Fuel Trim, Bank 2, system too lean. When I take off and come slow down for a stop sign and push the clutch in, the RPMs drop to about 400 and it gargles kind of and then they jump back to normal idle. I also can not cruise in the car at a steady speed because it will start bucking. Seems to be missfiring.. I had an exhaust leak where the header bolts to the Y pipe (gasket blew out). I replaced it, then it blew out again the next day..? Clogged cat??? The car has the following mods: SLP MAF, Edlebrock shorties with stock Y pipe, Corsa catback, and K&N Filter. What could be going on? Any input is appreciated. Thanks,
Jeremy
EDIT: I have an SLP Predator Tuner that came with the car when I bought it, but its locked on another vehicle. It will read Live data though. Like H02S voltage and Fuel Trim %. SO if Getting some of that info would help i'll go run it
Jeremy
EDIT: I have an SLP Predator Tuner that came with the car when I bought it, but its locked on another vehicle. It will read Live data though. Like H02S voltage and Fuel Trim %. SO if Getting some of that info would help i'll go run it
Last edited by MeatL0af; Jun 18, 2011 at 09:19 PM.
The common causes for those codes/symptoms include: fuel filter blockage/fuel contamination; exhaust leaks upstream of the O2 sensors; or air/vacuum leaks almost anywhere downstream of the MAF.
Thread Starter
Staging Lane
Joined: Aug 2006
Posts: 53
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Ok thanks alot. I did change the fuel filter already, though. I guess my first fix would be the exhaust leak again. My dilemma is the cat, though. I don't know if it's clogged or what because I've changed that collector gasket once already and it just blew right out again. It was a stock gasket though, so maybe they are just too weak for the big headers. I'm sorta new to LS1's because I used to have an LT1, so I don't know much about the vacuum lines and such. Is there a diagram somewhere I can view?
Jeremy
Jeremy
TECH Addict
Joined: Sep 2009
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From: PA/MD
not many vacuum lines on these luckily, the way you are blowing the gaskets out though does sound like your cats might be getting clogged. I know Summit racing has universal cats for around $65 each. To check and see if its your MAF giving you problems you can unplug it (this will throes a MAF code) and set the car into speed density mode bypassing the MAF
Thread Starter
Staging Lane
Joined: Aug 2006
Posts: 53
Likes: 0
not many vacuum lines on these luckily, the way you are blowing the gaskets out though does sound like your cats might be getting clogged. I know Summit racing has universal cats for around $65 each. To check and see if its your MAF giving you problems you can unplug it (this will throes a MAF code) and set the car into speed density mode bypassing the MAF
Jeremy
This may not be the fix, but try cleaning the MAF with CRC. I have a SLP lid with the K&N air filter and over time the car started having eratic performance. Cleaning the MAF with CRC Mass Air Sensor Cleaner ($7) fixed me back up in 5 minutes after driving for months with the car having a bad bog.
