I have an '03 Discovery II. I have never had any real problems with the truck. The guy I bought it from had a lot of stuff done prior to my purchase. I replaced the front drive shaft after I had a loud vibration issue and I found on this forum that it was a must to replace it. I replaced it and it was all better. So I am coming back to the forum for more help.
My Throttle body heater sprung a leak, which from my understanding is pretty common. I ordered the parts and while I waited I put in two new rear O2 sensors. The service engine light would come on every now and then and I couldn't drive the truck while I waited for the parts so I went ahead and put the new ones I already had in. I also did an oil change while I had the time.

I put in the new TBH and gasket and put everything back together. I took it out for the first drive after the repair and the truck was fine at first then ran sluggish and for the first time ever the SES light was blinking. It worried me so I took it to my local auto part store and had the codes read. It had multiple misfire codes. I had never had any problem with the way the truck ran before so I am curious if there is some correlation.

I am not sure with the amount of coolant that sprayed the engine if perhaps the plugs and wires just got soaked and they need replaced?? I figure if it was a head gasket or coil pack I would have saw some type of sign before replacing the throttle body heater....???