[shorod]

Welcome to the forum!

Why are you using 10W40? Do you otherwise have significant oil leaks?

When you have your foot on the throttle to keep the vehicle running, does the engine run roughly (assuming you are keeping the engine speed around 1000 rpms) or smooth?

The P0171 and P0174 could easily be due to unmetered air entering the intake. Unmetered air would be any air entering after the Mass Air Flow (MAF) sensor. This could be due to intake air tubing that is not properly connected, a bad vacuum hose, or other vacuum leak.

The idle issue could also be due to the unmetered air, especially if the leak is sufficient enough to cause a rough idle. If the engine is smooth when running, then I'd suspect you also have a bad Idle Air Control (IAC) servo. These are pretty common to fail and cause hard starting and idle issues on cold engines with no other symptoms when off idle.

-Rod