It might be worth doing a test to see if an older decoder does the same thing in the same place with the same loop set up, that could help find the cause. I have heard of cars not counting consistently and transponders picking up intermittently on the new decoders. It's not always easy to find the reason for laps being missed or having low hits, as Bob suggests, test the loop first as it's the place where there may be potential 'decoder issues' involving the loop and/or connectors etc.

Regarding transponders not counting, 'pure' RC4's are not backwards compatible with older decoders (don't work at all) and older MRT's need upgrading to the 'NS' new system spec to work ok (the new type flash twice when powered up, old type don't flash). Details/help about trade in's/PTX (NS) upgrades and offers
HERE: http://bitly.com/mrt-help or send me an email: [email protected]