Holden Barina 2000: Why does my car randomly lose momentum?

Diagnosing problems like this one are difficult, Willie, mainly because you can bet your bottom dollar that the car won’t reproduce the problem when your mechanic drives it. But three or four times every tank of fuel is not funny and, should the problem rear its head just as you’re about to enter a busy road or turn across traffic, it could be very dangerous, too.

But the fact that the car runs perfectly most of the time suggests that it’s not a problem with any of the actual, mechanical engine parts, or it wouldn’t run properly at all. That leaves you with fuel, spark or the computer that controls everything as your most likely suspects. A dodgy sensor such as a crank-angle, camshaft-angle, temperature, oxygen or throttle-position sensor can cause problems like these and sensors have definitely been known to throw up intermittent faults.

The best bet is to have the car scanned by a dealership or workshop with the correct computer gear. Otherwise you could be chasing your tail for weeks, wasting time and money as you change sensors that were working properly and still not fix the problem.