Ford ka misfire
My Ford Ka is still misfiring...and I've trying to solve it since Chrismas 2010. 4 different garages have looked at it, and cannot solve the problem. I have been told it's the ECU but I don't believe that, as either they work, or they do not. Or they go into some kind of safe idling mode.
I've just about checked/replaced everything obvious: coil, plugs, leads, TDC sensor, injectors. No leaks on intake manifold. Changed oil and added cleaning agent - no sticking valves. Compression OK on all 4 cylinders. Checked for bad earth connections. No error messages on diagnostics port.
perfect start on cold & no misfire even at full throttle, but after about a mile it misfires terribly, almost not possible to drive. Press the accelater a little bit and it misfires badly. Then, after a good half hour run, including a blast on the motorway, it gets better to the point that I can keep up with traffic in the fast lane, press the accelerator all the way down and there is no problem...
Then I leave it overnight, and it's the same story again.
What can it be? It must be something blindingly obvious, but I don't see it !?
2 things worth considering. If your Ka is fairly old it will have an oil filler cap with 2 pipes coming from it. Remove the one that goes to the engine and check the small hole in the cap is not blocked. Also, that the filler cap itself has not corroded inside and causing a blockage. It should be a wire gauze and not a hard lump of solid rust. Maybe check all engine breather pipes are not blocking up which would fit with your symptoms.
Originally Posted by Jim1064
Do not rule out the ecu. If the misfire has at any time previously been caused by a faulty coil pack, the coil can 'spike' the ecu and may cause all sorts of running problems. You can have it tested once you have exhausted all other possibles. I use BBA-Reman but there are many sites offering this service.
Idle Air Control Valve?
These I know from experiance play up/stick on Ford Ka's (And Ford Scorpios) although doubt if applicable to above symptoms - just a thought to mention - Although Hometune would be better to advise and rightly so.