Recently completed a valve cover gasket job on my 2013 5.0L

Everything has been running great except for a strong gas smell at startup and for the first few mins after.

Figured EVAP might be the cause and I inspected all the lines around then valve block but nothing appears disconnected or out of the ordinary?

Also did a code check at auto zone and zero codes came back which really surprised me.

Before I start trying a smoke test and further lose my mind, does anyone have a suggestion for what to try next?

 

I was curious on this one so I put it into AI. I don't know if you tried that or not. Good luck.

Fuel rail and injector o-rings — Same principle applies here though. On the AJ133 you have to disturb the fuel rails to get the valve covers off. Those injector o-rings are notorious for getting pinched or not reseating properly, especially if they weren't lubricated before reinstall. A tiny seep won't throw a code but will absolutely give you that raw fuel smell on cold start when fuel pressure is highest. Pull the intake manifold cover, start it cold, and look carefully for any wetness around the injector tops and bottoms on both banks.

Fuel line quick-connects — Double-check that every quick-connect on the fuel feed and return lines clicked fully home. A partial seat can seep just enough to smell without dripping visibly or tripping a code.

EVAP purge valve and hoses — You mentioned checking EVAP lines, but specifically look at the purge valve itself and the hose that runs from it to the intake manifold. On these engines, that connection is easy to leave slightly loose or kinked during reassembly. A small vacuum leak there lets fuel vapor bypass the charcoal canister and vent under the hood. Again, more noticeable at startup when the system is purging.

Breather/PCV system — The AJ133 has crankcase ventilation hoses that route through the valve covers. If one of those nipples or hoses got cracked, left off, or not fully seated, you'll get oil vapor and fuel vapor venting into the engine bay. Check every small-diameter hose and nipple on both valve covers.