97 Jimmy rumbling noise at idle
My 97 Jimmy has a couple of issues that have all occurred at the same time so I'm
assuming they're related in some way. At first there was a low rumble from under the
vehicle. It went away then started again but only when in park. While in drive or reverse
it would stop. Now with the addition of a rather rough idle the rumbling noise has
increased in volume audible both inside and outside the vehicle and now the rumble can
now be felt throughout the vehicles floor, and into the steering wheel. It goes away by
simply increasing the throttle by about 100-200 RPM. Also on occasion a very similar
noise can be heard coming from seemingly under the dash panel by the defrost vents.
I've never encountered anything like this so I have no idea where to even start.
I'm suspecting the EGR is partially open all the time because it's full of carbon and unburned residue~ pull it off and clean it with a little carb cleaner and small brush~ test it to make sure the electricals are good on it~ https://www.google.com/#q=97+Jimmy+EGR+valve&tbm=shop
it's purpose in life is to re-introduce inert gas (exhaust gas) back into the intake upon deceleration and when combustion temperatures are getting too hot~ (for aluminum heads for example)~ when it's stuck open you're getting mostly inert gas causing not to run properly~
Possibly a resonator or converter coming apart inside the exhaust or cracked flywheel
