07 NBS Idle surge issue

[Blown03]

Just recently, my 07 NBS started having a small idle issue. Only happens in Drive or reverse. Usual idle seems to be around 600rpms. When warmed up and at a red light idling for ex, the idle goes down 100-150 rpms, the truck surges kinda and jumps back to 600ish rpms. It happens every 5-15 seconds. The best way to explain the idle surge, it kind of feels like when the A/C is running and the compressor kicks on, Thinking it was bad gas, I threw some seafoam in, and it did completely clear it up till my next tank of gas. Now it's back. So I cleaned the MAF, throttle body, air filter etc etc. Still nothing has worked.

 

Possibly a bad o2? I don't have any engine codes, but for the simple fact that injector cleaner cleared it up temp, leads me to think it's an o2.

 

Any thoughts are greatly appreciated!

 

Thx,

 

Dan

 

(PS 56k miles if that helps)

[Blown03]

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