Running Lean

MANDOsc303

Registered User
I have a 1990 SC just put an engine out of a 1991. I changed it from automatic to manual. Since I finished my car is been running really bad. today i did a KOER test and this codes came out: "OXYGEN SENSOR INDICATES SYSTEM LEAN, LEFT SIDE AND RIGHT SIDE", "INSUFFICIENT MASS AIR FLOW CHANGE DURING DYNAMIC RESPONSE TEST", "INSUFFICIENT THROTTLE POSITION OUTPUT DURING DYNAMIC RESPONSE TEST" AND "KNOCK SENSOR NOT SENSED DURING DYNAMIC RESPONSE TEST" I changed the TPS and MAF and still the same.hope some one can help me out.
 
Running lean

I have had to tap the manifold with a hammer to get the Knock sensor code to go away. also if you do not sit in the car and floor the accelerator at the right time you will get insuf. throttle position codes.
I too have a 90 auto. converted to a 5spd. with a prototype engine and blower . I am also running lean.
Stephen
 
Sounds like the O2 sensors to me. Ignore the operator error codes, the important one is the system lean code which is probably the O2 sensors not functioning. Replace them it, should help.
 
Both o2's going at the same time is not likely, check for vacuum leaks or fuel delivery trouble.
 
Also check to make sure all of your grounds are connected properly, particularly the ones in the cylinder head area.
 
Actually, I've had both O2 sensors go out at basically the same time twice. One of the joys of being a multiple SC owner. And I second checking those grounds as I've had trouble in that area as well.
 
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