A couple of mornings ago I started my engine, let it idle for ten seconds, crawled away in first gear, upshifted to second at about 1,800rpm, light throttle again in second to about 1,500rpm, lifted off for 2-3 seconds round a gentle corner (in a housing estate) and the engine juddered. I put the clutch in straight away and the engine cut out without a second. It wasn't a stall, and nothing seemed untowards under the bonnet. I got back in, gritted my teeth and turned the key, and it fired up fine and didn't give me a problem. 76,000 miler, never had a problem like this before or since. Any clues?