2004 Disco 2, We've had a lot of issues with the idle surging, nearly unable to drive it at times. I couple of weeks ago, I took the throttle body off and cleaned it, it ran perfectly after that for a day or two. A couple of days ago I ran some Sea Foam through the throttle body with the car running(per the instructions) and it ran great after that for a couple of days. Now it's back to the surging/poor idle. Why is this happening? Intake gasket leak? Why does it only run well for a couple of days after I clean the throttle body? No codes/lights on. Thanks Mike

 

Clean your IAC motor (silver unit with two hoses mounted on the intake manifold).

If it's dirty or sticking it can effect your idle.

 

X2 on the idle air motor. I was amazed at how gummed up mine was when I removed it for cleaning.

 

Thanks, I cleaned the IAC and I bought one on EBAY a few months ago I cleaned them both and tried each of them, still has idle bad problems.

 

Did you reinstall the IAC valve the correct way?
It's a 50/50 chance of installing it wrong.

 

There is a TPS sensor on the throttle body. I have yet to ever replace one, but it is possible yours is acting up.

When you ran the seafoam thru the intake did it smoke like crazy afterwards (normal if you have a lot of carbon buildup)?

Is your D2 setting any codes when it idles rough? How does it run with the A/C on? Normally the idle will be higher with it on vs off.

Check your intake manifold bolts, I know that sounds silly, but I recently ran into that issue when I was changing out my coil packs and it solved my squishy brake pedal (had been like that since I bought it). You could very well have a vacuum leak (especially if you have SAI) so check all your connections, and hoses.