left bank runing lean at high rpm

nwnsc

Registered User
so i got the motor instaled and runing this week end. i have code 91 comeing up when i get around 4500-5000 rpm under load. the book says it is left side going lean. it is a stock motor with a ported 90 blower no OD. check light will go out when you let off it after a min. what could cause this?
 
Stock exhaust with the O2 Sensors in stock location? Car idle OK and run normally other than this issue? Could be a bad sensor depending on your answers.
 
problem with the connector on the o2 sensor, or a bad o2 sensor. I believe lean reads a high voltage, with rich being lower voltage.
 
car runs grate! the motor is stock with 60,000 on it with fresh heads. i was suprized to see it made 14-14.5 psi at 5000rpm in 3rd with no overdrive last night. it was nice and cool out. the only things it has on it is a CAI, ported blower,and rasied top. allso has hiflow cats with no muflers. the O2s are farly new they where off my old 93. they have about 6-7000 mi on them
 
I got a CEL one day and the car ran horribly, wouldn't even barely idle. Pulled two lean codes, turns out I had a bad tank of gas. I put in a bottle of iso-heet and I was good to go.
 
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