2002 Chevy Silverado 5.3L P0106, P0107, P0300, P0171/P0174 - Post-Intake Gasket Replacement Still Shows Codes

Hello everyone, I've been experiencing rough idling in my 2002 Chevrolet Silverado (5.3L V8) specifically during cold mornings, but the engine runs smoothly once it warms up and especially in summer conditions. Last winter, I noticed several trouble codes including P0300, P0171, and P0174. After researching extensively on this forum and other resources, I concluded that a leaking intake manifold gasket was the likely cause. As a result, I replaced the intake gasket over the weekend. After the replacement, the rough idle disappeared and engine performance improved significantly. However, the Check Engine Light (CEL) remains on. Yesterday, I scanned the system and noticed two new codes appeared: P0106 and P0107 — these were not present during my previous code reading in winter. After clearing the codes, the CEL turned back on immediately, even under mild 40°F weather conditions. My question is: Given that I've already replaced the intake gasket, what could be causing these new codes? Is there another source of air leak elsewhere in the system? Should I let the truck run for a few more days to see if the codes clear on their own? Could replacing the spark plugs and ignition wires resolve the misfiring issue, or is this simply a symptom of running too lean? I'm not certain when my spark plugs and wires were last replaced — I purchased the truck about 18 months ago. Any insights or suggestions would be greatly appreciated. Best regards, Eric