On the US forums, this is the "A/C stumble".
Usual causes:
Ignition - plugs & wires (leads)
Engine fan not coming on
Idle Air Controller (IAC)

When you turn on the A/C at idle, the engine fan should come on - if it doesn't heat builds rather quickly and causes the engine to bog a bit. When you're moving and air is passing thru the radiator, it isn't an issue.

The Idle Air Controller is right behind the throttle, and should increase the engine speed at idle when the A/C is on.

If you start you car and let it settle, RPM should be about 750 - 800 RPM.
Turn on the A/C and it should go up to about 900 - 950.

Good info, will check the fan out later today and was going to order new plugs and leads today.

I want to adjust the idle speed as it is to low but can’t see what type of screw is in the housing by the throttle cable pulley. It is bit tight so don’t want to put a driver in until I know it is the right fit. Does anyone know what screwdriver size head I should use and is there anything else like an alley key locking this adjuster in place. I’ve put this post on my Judder question and also as a new topic.

Hi, Ours does the same thing, it feels like a miss and was dealt with a year ago by replacing plugs, leads and coil but its now back worse than ever. The car hesitates or "judders" in Drive when stopped at idle, its not related to air con coming on or off, and now sometimes when gently accelerating away if the "judder" is in process the engine hesitates, knocks / ping briefly then picks up.

We also have a small noise occurring in the steering area somewhere, as you tun the wheel at parking speed you can hear a low "creaking" sound. Power Steering has oil in it.

Vehicle is 1 owner since new PTC 000 2003 Limited, done only 35,000 Km.

Does anyone know a good PTC mechanic in Sydney you would trust to look at these issues without paying way over the top with Chrysler ???

Thanks.

I've heard that Mark at Injection Perfection (Bankstown Airport) ph: 9791 3122 is capable of diagnosing issues on the PT's and has worked on quite a few. Not sure about the price though!

- Ray

phew, here i was freaking out that my PT will have it's engine shoot through the bonnet.
I went to one of those Kmart Tyre and Auto places for the most recent service and asked for them to look at this situation.
They had no idea what it was and hence couldn't fix it.
Thanks to everyone for this great info, when i go for the next service (at a much more respected mechanic) i will ask them to look at this and see if it helps.
BTW, stay away from Kmart Tyre and Auto, for the health of your PT.
Michael

Margaret Skinner wrote:
Hi, Ours does the same thing, it feels like a miss and was dealt with a year ago by replacing plugs, leads and coil but its now back worse than ever. The car hesitates or "judders" in Drive when stopped at idle, its not related to air con coming on or off, and now sometimes when gently accelerating away if the "judder" is in process the engine hesitates, knocks / ping briefly then picks up.

We also have a small noise occurring in the steering area somewhere, as you tun the wheel at parking speed you can hear a low "creaking" sound. Power Steering has oil in it.

Vehicle is 1 owner since new PTC 000 2003 Limited, done only 35,000 Km.

Does anyone know a good PTC mechanic in Sydney you would trust to look at these issues without paying way over the top with Chrysler ???

Thanks.

Is yours Inferno red in the Lidcome/Homebush, Parramatta road area

Mine was all mended a couple of weeks ago - in brief to help anyone else who may get this fault.

Engine stumble at idle when aircon on caused by radiator fan not coming on intermittently generating high pressure in air con system and shutting down a/c compressor, which made engine stumble.

Replacement radiator fan from Sam @ Mopar $550 including postage to Qld, fitting $88 Re gas $88. Re gas not necessarily required by I had it done, as it was 4 and a bit years old.