2.8 poor starting

[Dave E]

I have a 1999 2.8 and after fitting a tuning chip and removing it as the engine would not start it is now very hard to start I have disconnected the battery over night and that has made no change can this tuning chip have damaged the ecu or the pump the heater plugs are working ok and are only a year old the problem has only started after fitting and re moving the chip

help
:(