It all started on 21st May. I was waiting at some traffic lights, on my way into town to see a friend, when the engine suddenly slowed and stopped. No noise from the starter motor, no electrics at all. No problem, this was one of those moments when owning an unusual car was a benefit. Up with the bonnet and out with the crank handle. But no joy there either. Enter the young lad in the Triumph 2500, who helped me push start it. "Cool car, mate" (him of mine, not me of his, but Triumph 2500s are all right by me, particularly if they contain someone who is willing to push start your car!) Quixotic beast, it started normally when I went to come home.

Over the next few days it began to do other naughty things: starting badly; stalling; missing; losing power; boiling over; blowing noises coming from the engine. The days of cheap Citroën motoring seemed to be coming to an end. Easy things first though: I asked a mechanic friend for some new points and spark plugs. He had only the plugs in stock, but by then I had decided that the problem was much worse than that, probably a blown head gasket, so didn't take them.

I asked around, the usual sages. My friend agreed that it sounded like the head gasket. No water in the oil, or vice versa, but it could have been a leak to the outside. Someone suggested I check the compressions. Someone else reckoned the carby smelt flooded. Yet another said "don't assume anything".

Systematically I set to work. The borrowed compression tester showed the engine was worn, but certainly not bad enough to cause the problems I had been having. I dismantled as much of the carby as I dared: all the valves, needles and jets seemed all right. I was reminded that the last time I had this problem I had fixed it with new spark plugs, but last time the old plugs were horrible Champions, not the recommended NGKs. The spark did seem a bit weak and intermittent, but the NGK plugs were only 2 years and 40 000 km old, and looked in good condition. I'd got much more than that out of the plugs in my HZ Holden Ute. I tried the plugs from my D Super: they were no better. So the plugs didn't seem to be the problem. The old points were quite pitted, so I got some new ones and put them in. This resulted in some improvement, but not enough. Tried it without the condenser, then another condenser: no change. Timing was correct. Hmmph!

Time to let that problem incubate, try something else. The water leak I fixed with a changeover water pump. Now for the blowing noise at the engine. The oracles had thought it a cracked exhaust manifold. I set to work exposing the offender. Nothing wrong with the manifold, but the exhaust pipe was almost cracked through about 6 inches from the manifold, where it had been bent roughly to join to the manifold. Is it easy to remove a one-piece welded exhaust pipe from an ID19 without special equipment? You bet! Jack up the front, just behind the wheels. Jack up the rear at the towbar and remove the left rear wheel. Drop the pipe, swing its rear end to the left and out it comes. A quick fusion weld with the gas plant and back it went. Enough exhaust putty to seal the space shuttle. Problem solved. Who said Citroëns weren't designed for easy maintenance?

Back to the engine. Still taking forever to start, still lacking power. I tried another ignition coil, which made no difference. The high tension leads off another ID19 also gave no improvement. Ballast resistor was all right. Distributor was properly earthed. Cleaned all the connections, even the ignition switch. No improvement in the way it ran, but a loose connection on the back of the ammeter was what caused the electrics to stop: things were quite hot there. By now there were only three alternatives, new spark plugs, recondition the carby, or take off the head. Start with the easy one. I dropped in to see my mechanic friend, he still had the plugs taped together. Four shiny NGK BP6HS, preset to the correct 25 thou gap. Today I screwed them in. Oh bliss, oh joy, oh relief! Finally my old car was back.

So there's the message: don't ignore the spark plugs. If your mechanic wants to replace them, but they don't look worn, replace them anyway. Apparently they only last a few thousand km on unleaded fuel, which suggests they should be replaced at every service. As another mechanic friend says, new spark plugs are "the cheapest tune-up you can get".