I`ve noticed today while parked at work that the tickover on my 2.0 8v is quite lumpy and hunts from 800 rpm to 1000rpm. It hits 1000rpm, stays for a mo then drops to 800, then rises again, then after a mo drops. seems to have a regular rythm.
Also, with this problem I have a poor running from part throttle, mostly when I pull away from a stop. I.e junctions etc. If you slip the clutck just slightly you overcome this.
Since fitting a new water temp sensor and thermostat things have improved. But its not perfect.
Where should I start? Clean the afm, new plugs, leads, Any ideas would be gratefully recieved and tried. Just hope its nothing too expensive
On the intake manifold, you will find a valve (looks like a cylinder) at the front of it. It has a hose connecting to the top of the main air intake hose. Take the valve off and clean it with carb cleaner. It has a sliding mechanism inside which can become gummed with oil etc. I usually just disconnect the hose from the end of it and spray the cleaner in there.
Funnily enough, mine did it today when I was stopped at traffic lights. It sorted itself after I did a 0-60 at the green light
I have had it before and cleaning the idle valve did cure it. The last owner of my car gave me a tin of carb cleaner and specificly told me to do this if the revs start going funky.