Low Rev Misfire

[catman]

Hi all. I have a 2004 mk3 Mondeo 1.8 petrol. I noticed a couple of hesitations as I slowed down in traffic at the end of a perfect 30 mile drive.

When I came home, the car ran badly at low revs and misfired violently when accelerating, until it got to 3000 rpm, where it ran smoothly again. the engine mangement light also came on.

I thought that it may be a faulty MAF sensor, but I disconnected it, and it still runs badly. Any ideas?

Thanks

Tim

Edited by catman on Tuesday 28th April 05:07

[IanCress]

Might be worth re-seating the HT leads, and swapping out the spark plugs if they haven't been done in the past 20k miles. After that, you're probably looking at the coil pack.

[catman]

Hi Ian, thanks for the reply. I spoke to my friendly Mechanic today and he said the same. Plugs and coil.

I'd be surprised that the plugs could go off so suddenly, but would be pleased if that's all it is!

Cheers

Tim

[catman]

Just to conclude, the copper end of one ht lead was completely corroded away, to the point where half an inch or so was missing!

We were both amazed that there weren't any problems before. The coil was a mess too. New coil, leads and plugs and all's well again.

Tim

[IanCress]

Same thing used to happen on my wife's MINI. Every few months I'd have to remove the HT leads and take a file to the coil pack to remove the corrosion from the terminals. 2 were always fine, the other 2 were always badly corroded.

[catman]

It's amazing how well a car will run with a fault like this. I had no warning that there was a problem, but this must have happened over weeks, if not months.

Tim