Spark plug reading

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Shawn

Lifer
Apr 20, 2003
32,236
53
91
I need to fix this myself since it's out of warranty and I'm strapped for cash. Not really sure where to start though since I am not getting a CEL.
 

DivideBYZero

Lifer
May 18, 2001
24,117
2
0
Running rich is usually a symptom of a MAF or O2 failure. If not those then some component of the air/fuel metering system. The ECU runs rich to prevent running lean and causing (pre)detonation aka knock.
 

jaha2000

Senior member
Jul 28, 2008
949
0
0
Running rich is usually a symptom of a MAF or O2 failure. If not those then some component of the air/fuel metering system. The ECU runs rich to prevent running lean and causing (pre)detonation aka knock.

I would agree, ECU is in Limp mode, aka rich so it does not melt the top of the pistons.

MAF, O2 are great places to start.
 

exdeath

Lifer
Jan 29, 2004
13,679
10
81
Check for boost/vacuum leaks also. Could be as simple as a charge pipe coupler torn or popped off. If you have an accurate boost gauge make sure you are seeing the expected boost. A small leak under even a light load will richen it up but not stay under load long enough to pull the trims far enough to set a light.

Vacuum leaks are a bitch to troubleshoot on boosted cars because it runs rich under boost and lean in vacuum and the computer goes back and forth on the corrections so it looks like its working properly.
 
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