New to the forum and to Z's. I just bought a 05 base supercharged, headers, exhaust, 600cc injectors, wahlbro pump. It has turboXS UTEC for management. It has a tough time starting and the idle surges up and down probably 2-300 RPM's and about every 400 miles I get codes 1273 and 1283 which are lean in bank 1 and 2.

Can you guys please help me out with what could be the potential cause of this? There is no wideband on the car, or boost gauge (I will be getting both shortly)

 

I am thinking its an air leak somewhere.... Any tips on what to check first?

 

Also forgot to add that the engine stays revved until about 2 seconds after I let off the throttle and it feels like it is hitting redline at only 5500 RPM