Intermittent Computer PCM codes
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
These are both LEAN codes one left side one right--Typically they are a result from adding mods such as cold air intakes--Also check for vacuum leaks or any intake air tract leak in the air bridge assy.--- If you can get a scanner check to see where your LTFT fuel trims are--To get a lean code usually means the trims are beyond +20 %-
Go to this site to review diagnostics---
http://www.gearchatter.com/viewtopic8886.php
Go to this site to review diagnostics---
http://www.gearchatter.com/viewtopic8886.php
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
What MODs do you have???
Have you checked the PCV elbow for rot/damage that can cause a big vacuum leak?
Ducting between the MAF and the TB for air tight status.
BC
Have you checked the PCV elbow for rot/damage that can cause a big vacuum leak?
Ducting between the MAF and the TB for air tight status.
BC
Safety Car
Joined: May 2003
Posts: 3,814
Likes: 105
From: Dearborn Heights Michigan
My highly modified 2000 will throw the P0171 if the motor idles for around 5 min. If I drive off it doesn't. Has been doing this for several years. My mechanic tried to find the prob with no success. No leaks evident.I just reset the code and forget it.
Tech Contributor
Joined: Aug 1999
Posts: 16,376
Likes: 404
From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
Fred, that is from a cold start, right?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The ONLY real way to get to the bottom of your issue is to DATA LOG the PCM and see where specific sensor outputs fall.
The major sensors to monitor would be:
LTFTs
O2 Sensor Output Data
WIDE BAND O2 sensor readings
One or more of those values will be WRONG and will be easily seen.
Bill
The major sensors to monitor would be:
LTFTs
O2 Sensor Output Data
WIDE BAND O2 sensor readings
One or more of those values will be WRONG and will be easily seen.
Bill
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