I Have A 2001 Is300 And My Cel Is On. Codes Read Are P0171 And P0174.... Im Getting Horrible Gas Mileage And Also When Ever I Try To Stomp On The Gas Or Try A Jackrabbit Take-off My Car Hesitates And And Doesnt Take Off. Instead It Feels Like Its Chocking And Drops In Rpm's. If I Keep My Foot Down On The Gas It'll Continue Like This And Not Pick Up Any Speed. Also, If Im Idling And I Floor It Or Half-way Floor It. The Engine Will Double Rev. From 1000 Rpm It'll Go To 2500 Rpm, Drop To 1000 Rpm Then Go Up Again. Please Help Me Out Here. Also If This Helps... I Just, Like 1 Week Ago, Changed My Spark Plugs. I Have An Aem Short Ram Intake But This Whole Thing Happened Even When I Had The Stock Intake. Thanks In Advance.