i have a 98 Gsr im wanting to do the conversion to a p28 and im having a check engine light come on and when the car starts its real ruff and idle sucks it surges but when driving it feels fine? could replacing the o2 sensor fix start up and idle or would it b the chip it self im not exactly shure what kina chip it is.

 

If you suspect it is the upgrade chip you can temporarily bypass it by cutting the wire connecting J1. I'd put a switch on there anyway. That way you can always test things later on by flipping back and forth from the stock program to the chip.

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