Be careful with directing water streams at electrical connectors, coil packs, fuse boxes, etc. I have had 2 fords in the past that didn't take kindly to underhood washing. One of the cars had actually wicked water up into the connecter for the mass air flow sensor and it would kill the engine every time I took a right turn. That took me 2 months and a good data logging system on my PC to figure out. Yes - the water stayed in there for 2 months...
I still wash under the hood of each of my cars. I typically use a few mists of Simple Green (over an already wet engine bay to dilute the Simple Green) and then use a small sponge with regular car soap. If done often, this will keep the engine bay nice and clean. If you use any type of spray after cleaning, I do not suggest one that will leave an oily residue, as this will actually attract more dirt down the road that will be harder to clean off. You also need to be careful with spraying anything like silicone spray around the accessory belt, as this can cause belt slipage.
If your engine bay is very dirty, any detailing shop will be able to clean it with a hot water pressure washer. This is likely what the body shop did to your Taurus.
Thanks,
Dan