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Hello everyone
so changed the valve cover gaskets this winter. While I was in there I had all the injectors cleaned. I changed the plugs etc. Car starts perfectly. As it warms up it will rev up and down for 5 min or so on it’s own then settle back down again. I also feel like if I am driving briskly then take my foot off the gas rather than the car coasting I can almost feel the engine slowing the car down.
Any ideas?
1992 Xjs v12
Its sounds as if the Piston is sticking in the AAV 'Auxiliary Air Valve' which is causing the Engine to Hunt and Rev
up and down until it has warmed up
This is a very common little problem which is often the result of the Car being laid up or not used for some time
As such there is a very good chance that when you start to use the Car this fault will clear itself, or you could remove the Rubber Tube
And give it a Squirt of Penetrating Oil or WD40
Be careful if you remove the Tube as they can get very brittle and easily break
I would not try and adjust it as its only the sticking piston that's causing the problem
which as I say may well clear itself with more regular use
Engine Hunting is a Common Problem caused by a Sticky Piston in the 'AAV' where left to its own devices it can often clear itself or if not then a Squirt of WD40 or Penetrating Oil might do the Trick
02-26-2018, 01:33 PM
Irratic warmup
