Irregular idle when A/C is on - feels underpowered

[Lacostas]

Hello to this great forum (again)

So, for the last 6-7 months im havin a weird issue with the power of the car. It feels underpowered and it seems like its struggling to run sometimes.

It seems that when some stuff get activated (like radiators, AC on ) the car is struggling to keep the PRMs up properly.

I have changed Oil, filter, O2 sensors, Spark Plugs and Coils, Air filter, MAF sensor like 1 week ago and i hoped it would solve the issue but its still there. I have no idea what to do/check next

When the radiator or the AC gets on, the RPMs go "abnormally up" from 800 RPM to 1300 and then it falls below 800rpm and sometimes close to stall (car shaking)... Any ideas?

No CEL yet.

Any advice is highly appreciated :dance:

[dghii]

Look toward your electrical side...a bad voltage regulator (on back of alternator) will cause all sorts of weird behavior.

[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.