Any ideas on where to look? The idle used to be silky smooth but lately when idling the car coughs for a fraction of a second at random intervals of 2-3 seconds. Car is an 09 SF SC with 66k miles. Sort of sounds like it is missing a beat. Happens where warm or cold. As I said, no codes at all.
I guess the usual places - air/vacuum leaks, spark plugs and coils.

 

Yes. LTFTs / fuel trims. Figure if it's an air leak or not.

If not, go for a coil.

Check for pending codes, too.

 

My money is on dirty MAFS

 

I have what appears to be the same issue. Mine is intermittent and usually occurs when the engine is cold.

I'll be following this thread with bated (coughing) breath.

 

Might be better to get started as not sure the OP is doing anything.

 

I have been on a 2 week business trip but will be investigating over the weekend....

 

I ran BG44 in 2 tanks, and it helped the idle and improved fuel economy.

Not a sales pitch... it works.