just got done with a rebuild of my 02 gp gtp. N* TB, xp cam, zzp tune, 3.4 pulley, pacesetters, 180* tstat. i installed my wideband O2 sensor and its showing a lean condition at idle. no codes. as soon as i bring it off idle it goes stoich. the car has been sitting for 9 months with 3/4 tank of gas. this issue is confusing the h*ll out of me. im wondering if its old gas... vacuum leak... im not sure. any help would be appreciated. i lost the first engine due to a lean conition cuz im a retard and slapped the pulley on it with no tune.