Can someone tell me what the circled part is? I have a slight vacuum leak from the back of it. I currently have high fuel trim numbers. Could that be the cause? How do I solve that issue?
Thanks
Kyle

 

It looks like the IAC (Idle Air Control) that controls air into the engine behind the throttle plate. How did you find a vacuum leak at the iac? Leak at that gasket, leak at the hose? Does the engine stall? Its a little tight but it can be replaced fairly easy., If its just a vacuum leak replace the gasket and make the hose is in good condition first.


Aubrey

 

Thanks for this. That looks to be it. I bought a little automotive smoker on Amazon and plugged it in to the brake booster hose. I could see smoke around the back of the IAC.
The truck runs reasonably well although has a slightly rough idle and pretty poor fuel mileage (or maybe average? - barely 15mpg on the highway). Fuel trim numbers are in the high 20s.
I also thought a large vacuum hose connected to it but I guess not?

 

I just read that it is normal to see smoke from the IAC during a smoke test. So not an issue?

 

If smoke can get out unmetered air can get in. You shouldn't see smoke at the IAC in my opinion.