I have a 97 f-150 with a 5.4 in it and when the truck is on idle it shakes and acts like its going to turn off and my engine light is on and I don't think its the vaccuum hoses but some mechanic told us it was some sensor what sensor is it?

p.s after this started happening the truck uses gas like crazy!

did you check the crankcase vent valve? it's located on the passenger side valve cover, with a hose running to the back of the intake manifold, directly under the idle air valve, this connecter will rot out and cause a major vacuum leak, happened to mine, runs like crap, use's way to much gas
hth
Rick, Ore