Sonoma Idle Issue

Ya more idle issues from other vehicle.

My bros 99 GMC Sonoma runs great and everything. Just recently, while at idle you can hear it going fine, then there will be one "bump" every now and then. It's hard to explain and I may have to take a vid of it. It idles, then there's a little bump, almost like a misfire, and the whole engine shakes. It's really quick, but it just started doing this. I'm thinking it may need new plugs, but seems like the problem would be more constant. No CEL, and it doesn't happen all the time. Any ideas?

When was the last time the throttle body was cleaned? I've had some various idle issues on my 99 Sierra work pickup and for one of them I cleaned the throttle body and it went away, might want to try that.

Just cleaned actually. I installed a CAI on it and did the full cleaning on it. Also just replaced the TPS recently too as that went bad and clean the TB then also. Maybe 4 months ago for that one.

Could the CAI have something to do with the idle issue?

No because the sound is coming from the motor. It wouldn't cause an issue like that. Especially where the whole motor shakes when it happens.

When was the last time a tune-up was done? I agree, it does sound like a misfire, could be a bad plug or a plug wire grounding out.

Didn't do a tune up this year. Plugs were changed out 2 summers ago. Going to try those first.