Squealing from engine goes away with acceleration

[89comanchePeggy]

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?

 

[yxmj]

Check all you vac lines......sounds like one is off or cracked

[JMO413]

The MAP sensor hose just pushes into a rubber fitting on the back of the Throttle body. I would check there first.

The screw driver is pointing to the line. Mine will look a little different I taped the throttle body and installed a nipple. It's one of cruisers tips.

The bottom hole on the throttle body is the one that gets vacuum. The top hole is just there to hold in the factory rubber grommet.

[89comanchePeggy]

So when I replaced my fuel injectors i snapped That hose line. I replaced it using tapered elbows and some soft brake line. It did have a leak coming from the rubber gasket to the throttle body but i used some silicone gasket and covered up the leak. I’ll check it again but I’m pretty sure it isn’t this. 

[89comanchePeggy]

Turns out my intake manifold is leaking! So gotta get a new gasket in there.