Hi Scott!, i've been having this issue for a while now, my Jeep Liberty KJ 2006 runs perfect, but as soon as the temp gets to normal hot, if i use the AC the RPM drop nearly to 500 and my oil pressure light goes on, as soon as i drive or depress the pedal it goes away, and if i turn the AC off the light goes away too, what could i do?.
thanks in advance.
@cgtoro
Is it throwing any codes?
no codes, just the oil light
Load test the battery and alternator first. If they are fine, the AC compressor is acting up.
@yaser
but why when the temperature hasn’t get to the highest the AC works great?, it’s only happens when engine is at normal hot temperature, but only on idle, if i’m on the road the truck AND the AC both work perfect
Some vehicles have an electric switch attached to side of throttle body. If so, make sure it's plugged up good. When you turn the AC on the switch usually pushes on the throttle body lever, increasing the throttle. A vacuum hose off or a pcv valve also cause weird idle if bad or not pushed in good. Need about an 800 milliamp battery. If your battery is less than 650 milliamps it probably doesn't have enough power. I ran into the same problem, rough idling engine dying or attempting to die at a red light with a 93 Jeep Grand Cherokee and the owner's manual said 650 milliamp or larger.
@gunsmoke16
thanks, i’ll try to check what you said, but my battery has less then 4 months old and it’s an 800 amp
It may be your AC compressor is on its way out.
Is it misfiring at all with the AC off?
@inthrustwetrust
it does not misfire, with or without the AC on, i think that it doesn’t even stall, but the RPM drop (only with the AC on) and i think that is what’s making the light to turn on, i’ve noticed that the pedal is a little sticky when i start depressing it, could it be the throttle body somehow dirty?, i’m thinking that i should give it a try and see how dirty, the IAC sensor too.