Silverado 2500 question

ironman_gq

Posting here cause its not a Jeep but I know some of you guys are or were dealership people and might have some more experience with my problem. My truck keeps throwing a lean condition code on both banks. My question is whether you guys think this is the MAF, O2 sensors, or fuel pump losing pressure. The truck idles fine but occasionally has some bad hesitation right after startup in the morning and seems to be down on power. I have just replaced the fuel filter and cleaned the air filter so those are ruled out. Code is PO171 and possibly a few others I cant remember

rollen dean montoya

check your fuel pressure. it might cause the fault code but more than likely its your O2 sensors. i got to R/R them on the 97 astro, all 4 of them.

ironman_gq

Its worse on cold startup for the first few minutes its stumbles and has no power so the O2's shouldnt even be in the system yet cause theyre still cold. I tried cleaning the MAF and it was better for a little while. My next step is fuel pressure. I really dont want to replace the fuel pump ($300 and the tank has to come down or the box comes off)

rollen dean montoya

had to R/R the fuel pump in the jeep. wasn't that bad . took me and my son 2 hours total. you might check the fuel pressure regulator also. that could be the problem too. it should be on the fuel rail towards the rear on the left side if you have port fuel injection. not too sure on a throttle body set up.

ironman_gq

I know where the regulator is. I have the 6.0 so its SFI instead of TBI. Im really starting to think its a bad MAF cause its only a problem when the engine is cold and before the o2's heat up and go online. After that it runs great but has a check engine light on

mrtazwrench

Reseal the intake, it has a vac leak when it's cold. :t:

rollen dean montoya

i think taz just might have found it. should have thought of this but i blonded out. i do that being a blonde. keep up posted

mrtazwrench

I've not fixed one of these before, but was an obsever while one was in the middle of diag, commmon fix posted on the auto tech forum my boss pays for.

ironman_gq

Just checked fuel pressure thismorning I got 38psi and I need 55-60 for the system to work right. The regulators good and in the back of my mind I knew Id be replacing the pump eventually so thats my project for next weekend. Good news is is that I will finally have a working fuel gauge again.

ironman_gq

From what I can figure these engine will leak all the time with a bad intake. Its all plastic and a dry intake so there is no coolant running through it and they dont expand like a metal one will.

tufcj

Did a fuel pump on a friends '03 Silverado a while back. The tank was full, so it was actually easier to remove the bed than drop the tank. Bob tufcj

mrtazwrench

ironman_gq wrote
From what I can figure these engine will leak all the time with a bad intake. Its all plastic and a dry intake so there is no coolant running through it and they dont expand like a metal one will.

True, but I have had this fix a ford with a plastic intake, and a former coworker fixed a 6.0 chev just like yours, same issue.

mrtazwrench

tufcj wrote
Did a fuel pump on a friends '03 Silverado a while back. The tank was full, so it was actually easier to remove the bed than drop the tank.

Bob
tufcj

I've done quite a few pulling the bed, 8 bolts, if it has an aftermarket hitch that may cover the 4 rear bolt acess holes in the frame.

With 38 PSI I would start there also and see if that does it.

ironman_gq

Definately plan on pulling the bed off. I really dont want to try and drop the tank on my garage floor, If I had a lift it would be different but I dont (is on my list for the future, they are fairly inexpensive for what they can do)