Intermittent Idle Issue

[Woznaldo]

My car seems to be running fine but, on the odd occasion while idling the engine will change from a smooth steady idle to a lumpy 'might cut out' type idle. If I give it a rev while like this it sounds almost like it's missing a bit. If I then let it idle again it returns to the smooth idle again?

On one morning it was happening, I took it for a drive and it started to pop and bang on over run? Could this be a split in the AEI diaphragm? All the boost and vacuum hoses are new and it did it before they were changed?

In a couple of weeks I'll be taken the car on a 10 hour drive and don't want to be stuck on the side of the road with a car I can't get parts for. I'm going to take a spare clutch cable and a few tools anyway but would like to get any other stuff ordered soon.

Advice welcome.

Woz

[michael tierney]

try and vacuum test the aei unit or even try to blow through it, but it could just be a worn throttle bushing or a leaking inlet manifold gasket...check for play in the throttle shaft and loose manifold bolts!

[Woznaldo]

try and vacuum test the aei unit or even try to blow through it, but it could just be a worn throttle bushing or a leaking inlet manifold gasket...check for play in the throttle shaft and loose manifold bolts!

I'll check the manifold for leaks and loose bolts but I doubt that will be the issue as it's all pretty new having changed the all the head gaskets about 200kms ago.

How do I test the AEI? If I blow through it should there be resistance and if the diaphragm is gone I should feel little resistance?

[michael tierney]

if its good you should'nt be able to blow throuht it,or if u put a vacuum pump on it it should hold the vacuum!

[Nick k]

Afew things can cause this fault, Most common is crap in the idle jet causing a blockage at randon times, Another classic which will cause over run pops etc is when the king lead starts to break down. Worth a check of both. I don't think its the AEI diapham myself as the fault would be there all the time. I have a swirl pot bracket too if you need one still

[Woznaldo]

Afew things can cause this fault, Most common is crap in the idle jet causing a blockage at randon times, Another classic which will cause over run pops etc is when the king lead starts to break down. Worth a check of both. I don't think its the AEI diapham myself as the fault would be there all the time. I have a swirl pot bracket too if you need one still

Thanks guys. Might take you up on the swirl pot bracket .