Hi Everyone,
I have an 89 manual 2wd 4.0. Recently I did a full tune up on it and shortly there after, the truck started squealing when it warmed up. Kind of like a whistle. It happens only once the truck has warmed up a bit. It used to take about 5 or so minutes but now it is almost immediate. It has been happening for about a month. It seems like the sound is coming from the throttle body (sound goes away briefly when accelerating or depressing the throttle lever).
It also just recently developed a rough idle/ hard start when starting it warm. it's only rough for about 1 min and then once I start driving its gone.
Anyone have any suggestions?