the co trim should be +-25% otherwise it effects the overrun fueliing(i think it is) i was told to keep the co trim between this.

and at 75degrees water temp, is a tad cold, should be more like 85
if that was up to temp then is it running just water? as it will run colder with no antifreeze.

tps could go down a bit, you can get to 0.07 or -0.12 that will help


other than cam timing being out, an inlet air leak or high fuel pressure then the chip needs adjusting