Hi-- First of all- I should say I am not mechanically inclined lol!! I know some basics, and thats it! Anyways any help I can get would be great!

I have a 99 Ford expedition

First and foremost current problem- My expedition will start- But unless you keep your foot on the gas it dies! It happened on wed- It was the coldest day ( I think) of the year and I drove it to work, no problems! I get out of work- And it will start but not stay on! I had to get it towed home that day- and I thought maybe- I know unlikely but maybe the fuel lines froze up- so I just let it sit and warmed up today- And I went out there and put some HEET in my fuel tank- Someone told me to try it, And then I left my hood open - hoping it would thaw out. ANyways- It didnt work- and is still doing the same thing- I checked my fluids and all seem to be fine.. Anyone have any idea what it could be?/ And could it be an underlying problem to my 2nd problem which i will post now

2nd problem- I bought my expedition2 years ago- and about every 3-6 months i have had to take it to the shop.. I guess what they say is happening is my sparkplug coils are blowing and needing to be replaced one at a time. The first 3 mechanics I took it too- Said that the engine had to be replaced- And of course the used car warranty I had- Would not cover that. Well that wasnt an option- I took it to a family mechanic- And he said they do have temperary fixes. They put a "boot" around the spark plugs- Which will help prevent the spark plugs from blowing- But if one of the ones that has been replaced blows again- then they will not be able to fix it.. So far 4 have blown- But its been a different one everytime- So luckily they have been able to continue doing it.. I have been told that this is a VERYYYYYYYYYYYYY common problem in 99 ford expeditions- but not common enough for recal. Ireally dont have the money to get a new engine in my truck, and I really dont like having to pay 250 everytime a spark plug blows- At least 2 times a year.. Does anybody know anything about this and can you give me any kind of input? Thanks so much!!

Lisa