bad idle 3.9 classic

[adrian edge]

I am having an idle problem with my 3.9 classic at idle it seems to pulse every so often not a constant problem just wondering if this is a fault or just a rover trate.

cheers edgy

[raglan_jack]

Hey mate - i had a similar thing on my 97 3.9 and after changing everything i could myself to try get it to idle i went and got it hooked up to a diagnostics and found it was the air flow meter / air mass meter

[bee utey]

Could also be the IAC (idle air control) motor, screws in the back of the manifold. Try unscrewing it and cleaning it with carby cleaner.
Sometimes all you need to do is raise the base idle speed, 3/16 inch allen key on top of the throttle body, open (anticlockwise) with a hot engine until varying speed stabilises.

[camel_landy]

It could be lots of things... So probably best trying to diagnose instead of throwing money at randomly replacing parts!

The bad idles I've had in the past have been down to either HT leads or head gasket!

M

[LOVEMYRANGIE]

Try this first. You can do checks to find any problems with the MAF and TPS with the info in the pdf in the linked post below.
Dont throw any coin at it until you have done this!

http://www.aulro.com/afvb/1092934-post12.html

Cheers

Andrew.

[roverspec]

do a simple test first .

Take off the platic T piece in the breather lines off the plenum chamber. In the t piece the is a tiny hole that gets carbined up, give that a good hit with carby clean and try to blow through it.

This is a piece that gets forgoten but can muck with the idle.

Try it an see.

carla