Chugging while accelerating with A/C on

So I've been hearing this "chug chug chug" noise when I accelerate from a complete stop. So I give it more gas and it goes away. Once it hits like 20 mph, there is no chug chug noise.

It sounds like those full size diesel trucks when you hear them on the road accelerating from a stop.

It only happens when my A/C is on. When the A/C is off, truck accelerates smoothly.

There is no check engine light. I checked the spark plugs and they're good, changed the air filter a month ago. About 45k miles on the truck.

Any ideas?

 

That basically narrows it down to the a/c. I would guess the a/c clutch or bearing is going bad.

 

Solved!!!

So apparently this was due to all 4 of my tires being low in air. My TPMS light came on and after measuring all 4 tires they were around 23 psi. So I pumped all up to 35 psi. Now the chugging is gone. I'm guessing the low tire pressure was causing the engine to work harder, hence the chugging especially when the A/C is on which also adds work to the engine.

So after pumping up the tires, have not heard the chugging in 3 weeks.