Hi, i have vw polo classic 1997 model, 1,4 l. the engine switched off while i was driving and i parked on the road side. started the car several times but it was just cranking.checked fuel and it was coming from tank,checked all the HT leads even the one from the coil and all connections were sound but did not start again .after leaving it for about an hour i started the engine and it worked till i got home after about 7kilos .it did not stop again .what could be my the problem