My TH magna seems to idle a bit rough when the engine is warm. No problems when it starts but the idle needle when in Drive just doesn't seem smooth. I've cleaned the air filter, throttle body, tighten all bolts, changed leads and all 6 sparks, new oil but still can't get rid of the rough idle. Any suggestions on what this could be?

Dirty MAF sencor could be the reason, try cleaning it. Although in my case it was more then rough idle, car was actualy missing in lov revs aswell as very rough idle.

it will be the iac stepper moter that is causing it does it go up and down from bout 800 to 1200 revs?

I had that same problem - the stepper motor, ISC (idle speed Control) - i cleaned it put it back in - and it was all better for a while, then it started again, so i changed the motor. If you live in NSW there is a place sells after market ones to suit ur car for about $110 otherwise its approx $250-$300

Oh i should say, I also had a HIGH IDLE problem - it wasnt fluxuating just high and if u pushed the accelartor and just let go it would bounce up and down once, i reset the ecu, let it heat up on idle, then it was alllllll sweeet, even drove smoother.So give that a try before the ICS change.

This might sound like a stupid question but where is the ICS? Can I spray carby cleaner into the airflow meter? I only notice it when I put it into Drive gear, when it is in neutral it sweet as. Gear box is new from a TJ. Could that be the problem?

its on the bottom of the throttle body that black thing sticking out under it

its on the bottom of the throttle body that black thing sticking out under it

So I just pull it apart, give it a good clean and then put it back together? Is it the one that controls when the gears change?

HUH i dono if it does that... i have a manual... Did you try the ecu reset first?

SORRY its ISC (idle speed control) - ummm....type ISC magna... Type it in google images - isc magna TH - its hte first one that comes up... it has a 6 pin plug... and it is under the throttle body..

not under - its below it...i.e. if you look at the throttle body on a side so that you see hte complete circle... its below that.

I've resetted the ecu and same thing. Might have to check out the ISC.

not under - its below it...i.e. if you look at the throttle body on a side so that you see hte complete circle... its below that.

Thanks mate. Too late now but we'll check it tomorrow.

I have about 6x ISCs you can take your pick from. PM me for info. It would pay to clean out your PCV valve - the little black plastic elbow on the front tappet cover. Likes to gunk up. Renewing it is a good idea. Typical prob on TE-TH and high milage city driven cars. Will soon be a prob on early TJs

I have about 6x ISCs you can take your pick from. PM me for info. It would pay to clean out your PCV valve - the little black plastic elbow on the front tappet cover. Likes to gunk up. Renewing it is a good idea. Typical prob on TE-TH and high milage city driven cars. Will soon be a prob on early TJs

Thanks mate. We'll try it and see if it makes any difference.

Also check your engine mounts, it could be working perfectly fine but if the engine mounts are shagged they won't be absorbing vibrations and making it quite rough in the cabin.

Also check your engine mounts, it could be working perfectly fine but if the engine mounts are shagged they won't be absorbing vibrations and making it quite rough in the cabin.

yep i agree