Whistling Noise Under the Hood - FIXED!
Fixed! My two year teapot whistle is gone.
I checked for vacuum leaks with cleaner but found nothing.
The throttle body definitely needed cleaning so I took it out and gave it and the IAC a thorough degrease. It did NOT fix the whistle, but I noticed the whistle was different. Instead of whistling when it was out of gear between shifts, it mostly whistled while in gear just before the upshift for gears 1, 2 and 3. Weird.
When I took the throttle body off the bolts were firm but too easy to loosen. I merely made it a little more firm on the re-install. After cogitating on the whistle change, I figured I'd tighten these bolts some more. The whistling only occurs in cooler weather when the engine is warming up, so I waited until morning when it was 50 degrees and went for a drive... The teapot whistle is now completely gone.
A guy on a YouTube video said he just tightened the throttle body without worrying about the torque spec as it didn't matter. Apparently not. I didn't bother looking up the torque, for my test drive I just tightened it very firm but didn't go crazy.
The throttle body gasket was very thin but in very good shape. Next time I clean the throttle body I'm going to either put in a thicker gasket or maybe two thin gaskets. Then I'm going to torque it to spec.
2004 Rubi TJ Low COG Recipe: 33x12.5 tires under flat fender flares, 1/1.25 inch motor/body lift, 2.5 inch OME suspension lift, all new JKS upper/lower control arms, more...