[Brett]

whats your earth strap like?

had a dodgy earth stap on my van once and it wouldn't start with the air cleaner on. i could start it with it off but when i went to do the nut up for the air cleaner it would die. you could see a little spark with the lights off when i did it. i have no idea why it stopped. took it to a auto sparky and he told me to replace the earth strap. put the earth strap on and it ran fine.

clean up both ends on the strap and see what happens.