Butterfly Valve Question

[red87]

Hey all,

Yesterday my died at a stoplight. It started running a little rough and it felt like I lost most of my brake boost just before this happened. It was difficult to restart and required lots of throttle to keep it running. While I drove it from the light to a safe place to park a couple hundred feet away it barely ran and I could hear a metallic rattling underhood, like washers in a can. This was not the sound of detonation and the CEL did not turn on. I let it idle at the place I parked it for a little bit and it sounded like some metal was bouncing around in the motor, near the intake manifold. I was able to check the end of the butterfly valves later on that night and was able to wiggle the end enough to make a noise. I'm assuming this means I need to replace the lower intake manifold with the newer piece. My thoughts are that the bushing failed at the stoplight, which caused a big vacuum leak, causing enough unmetered air to be admitted that my truck stalled out and causing my brake booster to lose enough vacuum that it became ineffective. I need to order parts after work today so I can fix it this weekend so I'm hoping someone can chime in and verify my diagnosis. Thanks in advance.

[LaOutbackTrail]

Makes sense to me.... hopefully you didn't have any pieces fall down into your motor and that just the bushing let loose. When I pulled my lower intake manifold the valves were audibly rattling, but I was not able to hear it when the engine was running...

Just so you know, I mixed up two vacuum hoses on the back passenger side of the motor. It caused the truck to loose the brakes and idle very rough as you describe. Check those two hoses (about 3/8-1/2"ID if I recall).

[off-roader]

Yup, that's what they sound like when they are ingested.