irratic idle

[96calais]

fella's car has been running a treat, but of late the idle is not right as i pull up to a light the engine almost stall's and then capture's itself again and seams to miss fire every now and again in drive, in neutral it idles a little higher of coarse and is better when driving it's smooth as. any thought's???

[304runner]

Have a good look at the vacuum hoses. These can have a hair line split that will cause this. But really it could be anything from dodgy fuel to a coil pack?

[mr calais 5.0]

Might be a throttle position sensor? Mine would not idle in drive when slowing down at the lights and had to have 1 foot on the gas and 1 on the break to keep her running..

[RX25SE]

Assuming the plugs and leads are OK, the throttle body and IAC are clean and the coil packs and DFI are OK, I would remove the DFI and mounting bracket and clean the surfaces where the DFI mounts to the bracket (add a little more zinc oxide grease) and where the bracket mounts to the engine.
A good connection to earth is important as the PCM uses the DFI to control idle speed (with the IAC) by altering the ignition timing.

Mine used to almost stall when shifting from reverse to drive (you could feel the IAC trying to catch it) and this fixed it.

I assume its a V6?