5L hunting for idle

[Noy]

ay guys today my car started to hunt for idle but does not stall but stays between 600-700rpm, recently changed the o2 sensor.

Also the ignition module, coil, dizzy, and external fuel pump have being changed in the last 6months. SO thats why ive come here to ask what would make it hunt for idle.

Cheers

 

[dirt drifter]

hmm. maybe the IAC (idle air control) motor in the throttle body might be broken or seized up? or a vacuum line may have split? i know a vacuum leak made mine hunt real bad

 

[Jayme]

ive seen a 5L with about 18 deg base timing hunting really badly. putting in the diag paperclip and turning the dizzy back to 10 deg fixed it straight up. maybe try that.

 

[greenfoam]

Mine hunts like that on some batches of BP ultimate, could also be timing out but I'd try another tank of juice first

 

[Noy]

Yeah it seemed to get worse as the fuel got closer to empty, just put some new petrol in it. Seems to be missing slightly also which has just occured when at operating temp..changed the plugs not long ago and changed the leads today. Coil and dizzy and ignition module have being changed using brand new parts.. so any help is appreciated

 

[dirt drifter]

if the fuel seemed to have something to do with it maybe try a new fuel filter? i spose u can safely rule out any ignition components being the culprit. my vs had a hissy fit recently due to a loose earth lead, got a real bad miss once she got up to operating temp. maybe check ya battery leads and earths

 

[Noy]

Yeah took it down to my mechanic, his saying his pritty confident its the internal fuel pump. So ill change it and see how i go

 

[reaper01]

my mates vq does that to but it does it on gas aswell

 

[Darren_L]

Yeah took it down to my mechanic, his saying his pritty confident its the internal fuel pump. So ill change it and see how i go

if it was the fuel pump, it would die in the arse under throttle.
I'd be trying something else, or at the very least hook up a fuel pressure gauge and check idle pressure.

Check the MAP sensor vacuum hose that runs through the centre of the manifold and connects to the manifold under the throttle body area. It's very common for this hose to kink where it connects to the outlet, which means the MAP sensor reads wrong causing an unstable idle