KH Laser intermittent rough starting and losing power

[MungoDragons]

Looking for thoughts on an intermittent problem I've been having with my 1993 KH Laser for nearly 18 months now. There are two things which are happening - one is occasional (so maybe once a week or so) rough starts where I need to rev a bit to prevent the car stalling, usually the engine smooths out and settles down after a minute or so. The second is a loss of power (or hesitation might be a better word) while driving, again generally it clears itself after a bit of revving (whilst saying "oh golly" under my breath, especially if there are cars behind me). Once or twice I have noticed a puff of white smoke appear from behind just as it seems to clear itself.

Mechanic has had several attempts to fix, unfortunately has only been able to replicate the problem once in the workshop. Each time it has been to the mechanic the problem has seemed to settle down for a while though. So far have had ignition coil, ignition module, plug leads, distributor cap & rotor, coil leads replaced. Last service we thought we nailed it when I noticed the behaviour seemed worse on low fuel. The fuel pump was pulled and it had a bent strainer, possibly impeding the flow, and after replacement all seemed fine for maybe 5 or 6 months but now it's happening again. The car is 1.8litre, 5spd manual with EFI and has done approx 280,000km.

Any thoughts appreciated as it's driving me nuts.

Denis.