the hoses you discribed do the come out of the firewall and go to the black thing on the plunuim ??
if so its cruis control and its not going to make you truck run like that
last time I had an issue simular to yours we found that thier was air being sucked into the plunim through a hole ... grab a can off carb cleaner and spray down the engine wile it try's to run when it starts to run better that is where you leak is that is how we found the last one good luck
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