3.0 long term starting issue

[Barnstormer]

Hi. Have owned my truck for five glorious years with just one small problem. Sometimes it won't start! Been looked at by at least a dozen garages but no one can sort the problem. Longest it went between episodes was a year! Sometimes it wouldn't start for a week and then fired on the key! Been told both batteries are good. Well start on a backward bump but not on a jump pack. Help please?

[Albannach]

When it won't start, does it turn over? Do you have to charge the batteries to get it to go?

[Barnstormer]

Hi. No never had to charge batteries. After a bump or jump it will show full charge on battery tester. Batteries have been tested professionally and were ok

[Barnstormer]

And the turn over is either terribly slow or nothing!