Slightly rough at idle

When at a light with brake held, the engine is just a touch rough. It may be within tolerance, but it would be nice if it was glass smooth. Any suggestions what I could check into? The truck is new to me, 150K miles. Plugs were changed at the dealer by previous owner at 120K. I ran some Seafoam through it (added to gas only). Other ideas?

 

Clean the MAF sensor.
https://www.tacomaworld.com/threads/maf-sensor-cleaning.26177/

 

Id start by cleaning the throttle body and MAF sensor. Make sure you only use MAF sensor cleaner on the MAF, they're very sensitive

 

Put a scan tool on it to check for stored/pending codes as well as check the performance of intake components.

 

Also wouldnt hurt to pull the plugs and see what they look like or if they used the Iridiums. The iridiums come standard on the 4 cyl trucks and should be good for 100k.

 

Have you tried disconnecting the battery for 15-30 minutes to let the computer reset? This will also help the truck get used to your driving style.

 

I'm installing a radio today, so this will happen naturally.

 

It would probably be best to diagnose and repair the idle issue before making any further changes to the electrical system...

 

I want to be clear that it is barely rough, as in, I can tell the engine is running. My Jeep is always like this. I doubt anything is technically wrong, but if I can dial it in I'd like to try.

 

If the throttle body gets dirty it can cause a low idle speed which especially on a 4cyl engine will make them feel kinda rough, I'd start by cleaning the throttle body and then letting it idle for awhile so it can relearn it's base idle.

 

Just though I'd follow up... I cleaned the MAF and throttle body today and it seems to have improved the idle noticeably. The throttle body was visibly filthy at the plate edges and bore near the closed position, which seems like it could easily contribute to rough idle.