2002 Toyota Pickup Engine stumbles when in traffic or comin

Hi guys. I've been reading your posts for some time and I was hoping you could offer some advice. I have a 2002 Tundra with the 4.7L V-8. For the past month I have had an intermittent problem with the engine stumbling when I would slow down to stop. It appears completely random. A couple of days would go by without incident and then sure enough it would strike again. Each time, it would never produce a check engine light. Well now the problem has progressed and is more frequent. The truck finally threw a check engine light and the scan revealed cylinder misfire in #3 & 5. The mechanic changed the ignition coil packs for these cylinders and replaced all 8 plugs. Two days later, it happened again. Knowing that the '02 tundra is finickey about plugs, I removed the autolite platinums he installed and used the standard Denso plugs gapped to the recommneded gap. The problem is still there, but not has severe. I no longer get a check engine light but I still get a light stumble. I have checked engine vacuum. It was 22inHg. Leak down test responded fine. I replaced the PCV valve while I was troubleshooting. I am using a consumer grade Actron scanner with free frame and inspection/maintenance abilities. No codes are present and all systems report normal function.

I have noticed the following common traits to the stumbling. 1) always during deceleration near full stop or while idling in traffic. 2) always happens in the afternoon and not in the morning. Higher air temp and lower density.

Contaminated MAF sensor? Idle Air control? Vehicle speed sensor?