issues with cold cranking, running rich system too lean

[matt_ts357]

ok i had to have a used moter put in my 2000 z71 it spun a crank bearing and locked up. my servive engine light has come on saying bank 1 and 2 system to lean, when i crank it in the mornings it idles rough skipping and reving up and down untill it gets warm then it will idle fine. i have swapped al my sensors throttle, idle air, fuel pressure regulator and the thinkghat lets exaust into the intake form my old motor which were all working fine. what could be causing this i need help my gas milage is killing me thanks!

 

[Molson02536]

ok i had to have a used moter put in my 2000 z71 it spun a crank bearing and locked up. my servive engine light has come on saying bank 1 and 2 system to lean, when i crank it in the mornings it idles rough skipping and reving up and down untill it gets warm then it will idle fine. i have swapped al my sensors throttle, idle air, fuel pressure regulator and the thinkghat lets exaust into the intake form my old motor which were all working fine. what could be causing this i need help my gas milage is killing me thanks!

Start with the simple and find a scan tool like a tech2 and check your timing. Running lean can also be caused by a dirty or faulty MAF sensor, re-check all your sensors and sensor lead wires.

Keep us posted

Molson02536

 

[matt_ts357]

ok thanks ill check