02 yukon 5.3 runs rough for 5 min when cold

[marqed628]

02 yukon 5.3 runs rough like too much fuel. Idles at about 900 barely tap the gas pedal and rpm's jump to 2000 only lasts for about 5 min then runs perfect i have replaced intake gaskets cleaned throttle body replaced 02 sensors put fuel injection cleaner into gas tank and replaced air filter nothing has changed. it seems to get worse died 2 times yesterday morning outside air temp was about 10 degrees scanner says bank 1 and bank 2 is lean even after replacing 02 sensors anything else it could be???

[newdude]

Originally Posted by marqed628

02 yukon 5.3 runs rough like too much fuel. Idles at about 900 barely tap the gas pedal and rpm's jump to 2000 only lasts for about 5 min then runs perfect i have replaced intake gaskets cleaned throttle body replaced 02 sensors put fuel injection cleaner into gas tank and replaced air filter nothing has changed. it seems to get worse died 2 times yesterday morning outside air temp was about 10 degrees scanner says bank 1 and bank 2 is lean even after replacing 02 sensors anything else it could be???

I kinda want to say that it could be your Idle Air Control that could be goofing up.

[gforce]

Sounds like you could have a bad intake manifold itself. I have replaced a bunch of those. The gaskets fail due to the intake being warped

[eastcoasthd]

Originally Posted by marqed628

02 yukon 5.3 runs rough like too much fuel. Idles at about 900 barely tap the gas pedal and rpm's jump to 2000 only lasts for about 5 min then runs perfect i have replaced intake gaskets cleaned throttle body replaced 02 sensors put fuel injection cleaner into gas tank and replaced air filter nothing has changed. it seems to get worse died 2 times yesterday morning outside air temp was about 10 degrees scanner says bank 1 and bank 2 is lean even after replacing 02 sensors anything else it could be???

Sounds like your FPR.

It runs rough when cold because there isn't sufficient pressure available to richen the fuel delivery.

You will need to test your FP @ the shraeder valve located on Pssgr. side fuel rail.

VIN. T - static pressure (key on / engine off) 55-62 psi
VIN. Z - " " 48-54 psi

Also, FP should not bleed off more than 5 psi in 1 min. (key off / engine off)