I have a 96 ford ranger with a 2.3 liter engine that I have started having trouble with lately. In the past years since I have owned this truck it has started right up and ran perfectly but now when I try to start it I have to crank on it a lot longer before it will start and when it does it revs up really high but seems to idol down after a few minutes but seems to have a miss or I should say runs ruff. Does anyone on here know what could cause this problem? I have checked several things on the engine with no results so far and another question is what is this part and what purpose does it serve. I took it off and it has a plunger inside that I think should move when 12 volts is hooked up to it but there is no movement at all.