Hi all.
I'm new here. Been hanging around the forum for a while now.
I've been battling with my 2000 3.0 V6 S-type. So I did what any
good forum user should. SEARCH. But could not find something that
actualy mirrored my problem. Any way.

What happened was that I had this funky irratic idle at times. I would come up to a stop, push the clutch in to stop and the car would idle anything between 1500 rpm and 2500 rpm. Then. As I stop completely it would sit there for about 5-8 sec, then drop to idle, about 950 rpm.

Sometimes I would have to blip the throttle to get it back to "normal" idle.
SO eventualy I got fed up. This is after I removed the Intake manifold twice. Checked for vacuum leaks...everywhere. Nothing. Reset the ECU. Nothing. So on Saturday I decided to have a look inside the TB (throttle body) Mmm...very dirty I thought.
Grabbed the carb cleaner...spray...wipe. And then.
This thing makes a noise...like somethings loose. Opened the the TB by hand....THE PLATE WAS LOOSE...The two srews holding it was completely lose. Took some photo's for you to see. The marks on the back(engine side) shows how much it was moving. The photo from the front shows how this affects the closing.

Took it apart. Cleaned all. Refit all and locktite the two screws. FIXED UP. After a 100km drive the ECU saw that all is ok now and the car is back to normal. No more funky idle/rev stuff.

Thought I'd tell you guys. So if you do at some stage clean up the TB...just check the plate if its tight! Imagine those screws came out.....

 

Rotor welcome to the forum.

Awesome that you were able to fix the rough idle. I believe this is the first time I have read about the butterfly screws being loose.

 

Wow. Never heard of those coming loose before. Maybe messed with by someone previously. It tends to be a high idle that shows an air leak rather than an erratic idle, but can be that. Of course not many cars are manuals (a few more are on the UK forum) so few posts about even high idle.

edit: beat me to it!

 

I called it an irratic idle - had no other way to explain it. It's not as a high idle. Some days the car would be fine. And then ...just like that it would idle high, then drop to normal. It was just very difficult to find the problem as it would not stay constant.

But, now its fine again. Still need to replace the solenoid valve's for the heater. Have been reading on that. Soon. The idle thing had me for a while.......

 

Great catch, and thanks for pointing out this very unique issue....