crown vic

Probably the first thing to suspect is ignition. Assuming that your '99 still uses spark wires (and not the newer coil-on plug system), those are overdue for replacement. Also, the 4.6L engine has the spark plugs facing up, which makes the wells susceptible to moisture. I would blow them with compressed air and apply a thin layer of dielectric grease to the plug and the seal at the top of the well. While at it, it's probably a good idea to replace the plugs, even if at much less than the stated 100K miles.

Replace the COP boots; moisture is getting in there and grounding the coils. Use silicone dielectric tune-up grease on the insides of the new boots.

Where are the COP boots?

"Sharon Cooke" wrote: > harezichi wrote: > > I have a ?99 ford crown victoria and I am having a strange > problem > > Everytime it is real humid out or I get water under the hood > for any > > reason the car wont stay on. I will turn tghe key and it > will start > > but the secon you let the key go it will cut off unless you > hold down > > the gas. I know it is related to moisture because the car > works fine > > after it dries up. > > > > thanks for the help! > > Replace the COP boots; moisture is getting in there and > grounding the > coils. Use silicone dielectric tune-up grease on the insides > of the new > boots.

The coil-on-plug (COP) boots are what cover the little coil and sparkplug at each cylinder. If the boots aren't there, you've definitely found the problem. :)

bottom of the coil itself (the rubber part)

Wouldn't they short out on the engine block if the boot wasn't there to prevent the spring touching the block ?

They would, but the more common occurrence is this (see pix):

Yeah, my friend's Towncar had one of those failures...