Irregular idle when A/C is on - feels underpowered

[Lacostas]

Hmmm but it doesn’t seem to be the case since most of the symptoms don’t apply here

I think I may have to remove the throttle body and look for vacuum lines that are disconnected.

Would a disconnected vacuum line cause the above symptoms?

[JFP in PA]

Yes................

[blue62]

Instead of removing your throttle body to look for disconnected vacuum hoses and possibly causing more issues.
Just do a simple vacuum test.
It will tell you if you have a vacuum leak or not.

[Lacostas]

Ok here are some updates:

I removed the oil cap and the car sounded like its running rough (struggling shaking etc) BUT the RPMs stayed at the same level. What does this mean ?

The car was not fully warmed up tho - not sure if it matters.