Sticky Valves
 

Hi all.
I'm having a problem with my car, and I'm unsure what it could be.
Problem is that when the car is sat idling, its rough, the car shakes a bit and I can hear almost a cough or chuff noise out the exhaust every few seconds.
I've replaced the idle control valve, and cleaned the MAF, the problem was fixed for 30 seconds then carried on.

I'm now thinking it could be a sticky / stuck exhaust vavle(s).

If it was, do they get stuck all the time or do they work when you increase the revs?

I've also noticed, if i've been driving for a while, then stop with the engine running for 5-10 mins the engine slowly heats up so that the cooling fan has to kick in.

Also noticed, a few times now, once the engine has heated up like this, (sitting still for about 5 mins after been driving) the engine purrs pretty much perfectly, but once I move on, and the engine has had some cool air going through it, the rough idle comes straight back.

ICV has been replaced, together with sparks, ht leads, coil, cleaned maf.

Car is a 1.25 mk fiesta.


Any ideas?

Cheers, Jason

Change the cylinder head temperature switch.

Cure mine

Where can I find such a thing?

Where is the CHT switch located?
I've read its either under the rocker cover between spark plugs 2 & 3 or under the alternator?

Leak down test if you really suspect there's a problem with the valves.

I don't know what the problem is, I just know, from reading on the net, that sticky valves can cause a problem like I'm having.
I'm just trying to look at everything to get the problem sorted :/

Cheers.