When car slows and is taken out of gear, the revs drop to a normal level then flick up. When car comes to a stop the revs sit normally. Ne1 else had this 'flicking up' issue? Have cleaned out idle sensor with carb cleaner. Seems a little better. Sensor may need changing for a new one.

 

Sounds normal. It will sit at a higher RPM until car has stopped, it's to add a little throttle to aid smooth gear changing.

 

That's good to know. It's a bit odd though that the car rumbles when the revs drop before it flicks. But if it's normal fair enough.

 

Check the pcv vacuum hose to see if it has split. This can result in the hunting and revs fluctuating.

 

Just had a thought...about a month ago I changed my air filter and noticed a small hole next to the left rear screw in the air box cover. Would this have any affect. Air is being sucked through the air box so maybe it's affecting the idle when the revs drop and he car rumbles. Am planning to remove the whole air box and put a cone filter on anyway. Would a hole in the air box give the symptoms I'm experiencing? I haven't seen a mass air flow sensir on my car so can't check that.

 

It's to the left of the idle valve. It's a 3 piece section of tubing. The part number is on the label on this pic.

 

I'll check and have a look. What about the hole next to one of the screws in my air filter housing?

 

Does it look after market, like it was drilled through? or maybe it's were the resonator goes in.

Like this:


If the hole is above the air filter I wouldn't worry too much about dirt / debris getting in to the engine.

 

My air feed tube comes up from the front of the engine up to the airbox which is the original. It's a small hole where there's a break in the plastic next to the left rear screw. Resonator isn't in the same place. I was wondering if ne holes in the airbox cover would cause it?

 

Well if mine was like that then I would head for a breakers yard to get a replacement. I usually do that with mine if anything is a miss.

 

As I say I'm gonna remove the whole air filter etc so ill see if the rumble is still there.

 

I have a rumble on mine and I'm 99% sure it's the power steering rack / pump making the noise. As when I move the wheel right to left quickly I can hear the rumbling. It will make the noise from cold mostly just after starting and idling for a few minutes too.

Might be worth checking on yours.