Had the SAME thing happen to me about a month ago. My Coolant temp sensor blew out of the intake manifold (2001 NON-aluminum crossover, you know how that goes) and got coolant all over my engine and deep into the spark plug wells.
I used a air compressor to blow out all the coolant from the wells and replaced all the COPs with MSD blasters which are ~300$ anywhere except AmericanMuscle which prices them at 380$ for some reason..
Anyway with the new COPs the engine is running great. No more misfire under load, no more sputtering uphill, no more CEL, and most importantly, no more coolant smell.
Petunia - 05 Mustang 4.0 - Waiting for little brother to come of age
Matilda - 01 Cobra 4V 4.6 - SOLD
Bernadine - 09 Mustang 3V 4.6 - Daily Driver