Engine light codes p0300, p0303, p0171

So I have looked these codes up and have come to the conclusion that the front bank is running lean, I am having random misfires, and misfiring in cylinder 3.

Does anyone know the cause of this? I have 149,000 miles on the truck and today while sitting at a light, it began studdering and almost stalling without giving it some gas. I thought it would be a vacuum leak but after spraying carb cleaner all around the hoses with no success I sprayed the intake manifold thinking it may be the gasket. Still no success but I was unable to reach the entire area of the engine.

 

It was the mass airflow sensor. Replaced that and problem solved.

 

Whenever I see p0171 on a 1st gen Tacoma, I think MAF sensor but since you were having the problem at idle I didn't think that was it. It seems like the most common symptom for MAF is stuttering at higher throttle/RPMs. Glad it took care of it.