02 silverado 2500hd help

[Edward spencer Jr]

Changed a bunch of stuff and can't  figure it out. 

[davester]

check for codes?  Those O2 voltages look fairly low, so possibly a wiring problem there.

maybe describe what "stuff" you changed?

[Edward spencer Jr]

Changed map sensor, maf sensor, temp sensor, crank sensor, fuel pump, fuel filter, evap sensor, fuel pressure regulator, tps sensor. It is running lean and I cant find any vacuum leaks. Don't what else to look for.

[CamGTP]

Have you ever replaced the intake gaskets?

 

Can you smoke test the intake to find leaks?

 

Intake gasket leaks and injector o-ring leaks are the most common vacuum leak spots. I've also seen the EGR port leak on the early year trucks that came with EGR. Then you have exhaust leaks before the o2 sensors that can cause high fuel trims, usually broken exhaust manifold bolts are the cause.

 

I would smoke test the intake to see what you can find. Sometimes you can spray brake cleaner around the intake gaskets and watch the fuel trims, if they start to come down for that real quick moment then that is probably the issue.

[davester]

It's also common for the exhaust manifold bolts to break off.  When they do, it can draw air into the exhaust, making the O2 sensors read lean.  Look on both sides for missing bolt heads on the exhaust manifolds.