Thread: 3.9 v8 idle speed

Originally Posted by mandala1111

Hi there all,I have a problem with the idle speed on my series 1 disco 3.9. I have been overseas for the last 3 months and all was finr before I left with the engine.Now the engine has an idle speed of 2000rpm in park and drops to 1200rpm when at a stand still in drive.The idle is still smooth but just way to high.Any info welcome and thanks in advance.Shane.

1. Check the throttle cable at the air intake, the outer section is clipped into a hole and can fall out and jam.
2. Unplug the 4 pin plug at the DS rear of the inlet manifold, unscrew and clean the IAC (idle air control) valve and refit. Use carby cleaner or contact cleaner spray.

Thanks Bee Utey.
I had already checked the throttle link and it's fine.The idle air mix was a thought and I will check that.Will it be obvious when removed if it could be the problem.What stumps me is why the problem has occurred suddenly after just sitting there for 3 months.Also I can't find my carby clean so can I use kerosene or another cleaner.Cheers.

All fixed.I used my compressor on the idle air mix valve and all is fine now.