As stated above, the engine runs on 3 cylinders and it is No. 1 cylinder (timing belt side of the engine) which does not fire properly. I changed the supposedly obvious culprits (new spark plugs/HT leads) to no avail.

BUT the best part of the story is that if I remove the lead from the non-firing cylinder while the spark plug is in the engine, there is a healthy spark (say, 5 cm) from the end of the HT lead to the spark plug/engine block. And when I remove the spark plug and put it into the HT lead and touch the engine, the spark plug works OK. The firing sequence is the same as it was before.

I must admit I am at my wit´s end right now.

Either the misfire is mechanical (we'll get to that later) or electrical.

For electrical -- pull the plugs, take a look for any obvious issues. If none, swao the plugs around.

If the misfire follows the plug from #1 , plug is faulty, replace.

If not, swap the plug leads round on the coil to the misfiring cylinder. Is misfire follows lead, replace lead. If not, replace coil pack. (Although they're built to fire 2 plugs, they have been known to fail one side).

If #1 cylinder is still the source of the misfire after all that, dry and wet compression test.

The coil pack is a good lead, but as you proven that you have good spark then the coil pack may be OK. You need to do ASAP a compression test on that cylinder to exclude major mechanical issue.

Dear Sirs, here is the news: very poor compression on No. 1 and No. 2 cylinders, does not improve after the wet compression test. Guess I am facing head gasket replacement... :bang:
Funny thing is that there is no coolant in the oil or oil in the coolant - maybe the gasket failed between the 1st and 2nd cylinder?

Yep, the compression test would suggest that. It's often the way.

Back on the road... and my wife hoped I would finally get rid of the ole banger

Funny thing is that, IIRC, head gasket failed on my late Uno with 999 ccm FIRE engine at exactly same time/mileage (18 yrs, 220 kkm). Guess it is the time and not mileage which sends them to scrap. I am running on clean water instead of coolant right now to flush the cooling system. I was unpleasantly surprised that the openings in the gasket were almost closed by the rust - the coolant used was supposed to act as a corrosion inhibitor.

(CZ)enda said:

I was unpleasantly surprised that the openings in the gasket were almost closed by the rust - the coolant used was supposed to act as a corrosion inhibitor.

Click to expand...

Indeed, but when was it last changed?

Pop a bottle of a flushing agent (about £3 from factors) in with the water a couple of days before you flush and add anti-freeze: it'll help get rid of the rust.