Need diagnostic help....p0174

Motor is new. Vct is new. Imrc is new. Tb was cleaned. Intake was cleaned. Mechanic I took it to could find no vac leaks and gave up on it. I need my truck! Please help

 

system bank to lean Bank 2... Check the EGR Valve might have a leak or the intake manifold has a leaky gasket

 

Manifold gasket is new and mech rules that out when he checked for leaks. Where is the egr valve?

The mechanic was unable to find any leaks

 

If it's a 5.4 3V it doesn't have an EGR valve.

 

Well if you are getting a lean code then start with fuel delivery if you are not having issues with vac leaks, change the fuel filter, run fuel injection cleaner through the system, check the gasket around the air filter see if its rotted or missing pieces. Have you checked your spark plugs? Also the ecm will enrich the air fuel mix in an attempt to fix this, how does it idle when warm? Is it a 4x4? If so check the vac lines for that, they can leak and it is away from the engine so not as obvious a place to look for a vac leak.

 

I need to know if you have any modifications first. Please list any/all modifications.

 

All this started after removing the intake and the pass side head to fix pass side exhaust mannifold. However since then, engine is new, fuel pump is new, FPDM is new, Ircm is new, vct is new, spark plugs are new. It is 4x4, air filter is newish. Idles fine when warm. All air intake gaskets are new.

 

No mods at all.

 

So this started with the old engine, and continued with the new engine? Have you cleaned the MAF? Could it be faulty or leaking? Replacing the fuel filter is always a good (and cheap) idea. What about the O2 sensor, could it be faulty?

 

Old motor was run out of time, so I replaced it. Got rid of all the misfire codes but not the lean. Maf was cleaned. Don't see how the maf would cause one side lean though. Idk about o2, never experienced on causing this much trouble.