Rough idle with a/c on in gear.

[Ptawesome]

Hello fellow PT owners. I have a problem and have read other posts on this topic with quite a few replies but no outcome replies. Problem is my engine idles fine with the a/c off but when I turn the a/c on and put it in gear (auto Trans) the engine idles quite rough. Any suggestions?

[Busted_PT]

Originally Posted by Ptawesome

Hello fellow PT owners. I have a problem and have read other posts on this topic with quite a few replies but no outcome replies. Problem is my engine idles fine with the a/c off but when I turn the a/c on and put it in gear (auto Trans) the engine idles quite rough. Any suggestions?

Check the the fan is running while a/c on. Look at the tac for idle speed. May need to clean the IAC valve. Just some things to try. Maybe someone will have a definite answer.

[harrym]

Originally Posted by Ptawesome

Hello fellow PT owners. I have a problem and have read other posts on this topic with quite a few replies but no outcome replies. Problem is my engine idles fine with the a/c off but when I turn the a/c on and put it in gear (auto Trans) the engine idles quite rough. Any suggestions?

i had a similar problem and it turned out to be the fan. Replaced the fan and now OK.

[ptcruisersteve]

What year is your PT Cruiser and how many miles? Does it blow cold air when you turn on the A/C? Is the engine light on?

[harrym]

Originally Posted by ptcruisersteve

What year is your PT Cruiser and how many miles? Does it blow cold air when you turn on the A/C? Is the engine light on?

It is an '05 with about 70,000 miles. I replaced the fan at about 50,000 miles. The air blows cold almost immediately upon startup, and the engine light does not come on.

[JoeX]

@ 70,000 you might want to do a tune up if you haven't already (at least plugs). Over charge the AC system, (higher than normal pressure) will cause some vibration at idle.

[harrym]

Originally Posted by harrym

It is an '05 with about 70,000 miles. I replaced the fan at about 50,000 miles. The air blows cold almost immediately upon startup, and the engine light does not come on.

Originally Posted by JoeX

@ 70,000 you might want to do a tune up if you haven't already (at least plugs). Over charge the AC system, (higher than normal pressure) will cause some vibration at idle.

I had major work done at around 60,000, so (hopefully) am in pretty good shape. Scheduled for 70,000 is oil change and tire rotation.

[JoeX]

Maybe someone with more experience will chime in, maybe engine mounts alowing engine to move and shake... Just a thought.
Low Idle but there is no way to increase it.

[ptcruisersteve]

Found my torque struts on my 2007 PT Cruiser were bad and it was vibration at an idle. You might want to open up the hood, have someone else start up the vehicle, put a foot on the brake and measure how much movement you have on the engine when it gets put into gear, also when you step on the gas a little with the foot on the brake. After I replaced the torque struts it was idling great.

[Ptawesome]

Originally Posted by Ptawesome

Hello fellow PT owners. I have a problem and have read other posts on this topic with quite a few replies but no outcome replies. Problem is my engine idles fine with the a/c off but when I turn the a/c on and put it in gear (auto Trans) the engine idles quite rough. Any suggestions?

Well folks. My problem is solved, I replaced the IAC and now everything is fine again no more rough idle, runs great again.thanks to everyone for there imput on my problem.