Try switching out the start relay with another one on the control box, like the headlight or horn relay and see what happens for a few days, if the fault returns it may well be a faulty starter. BTW check the pwr cable on the starter is tight and the main earth connector on the body is also tight.

 

I will try that thanks!

 

It could be the starter and usually by taking a hammer and if tapping it when it acts up the car starts you probably do have a bad starter...

Ground wires are another known problem...
Follow the negative lead from the battery to the body/frame of the car... Remove the bolt where it's connected there and clean (scrape/sand/wire brush) all surfaces... Add some silicon gel (available at most auto parts stores) and re-assemble...
Check all ground wires going to the engine block, transmission, frame...and clean them also...
Dave

 

I'll go with the starter. The carbon 'brushes' that conduct electricity to get worn down and sometimes tumble in their passageways in such a fashion as to lose contact with the commutator and the starter doesn't work. Tapping the starter with a broomstick or soft metal rod sometimes untumbles the brushes enough to allow the starter to become, at least temporarily, functional. Easy to replace if you have access to a lift and not real expensive if you have a good shop do the work. You can get credit for the old starter in many cases.