Vibration from Hell!
I have a vibration in a 2004 Grand Cherokee with a 4.7 engine, 2WD, and no modifications.
I need help solving this issue because it is driving me nuts! It has had the vibration since it was purchased in July 2003. The vibration starts at 1500 RPM whether it is in drive, neutral,or park. I can put it in
neutral at any speed and the vibration stops when the rpms drop below 1500. Also, it is more pronounce when cold
and slightly subsides as it warms up. It never goes away.
I have replaced the following starting in November:
Transmission, torque converted, and flexplate.
Power steering pump, water pump, all pulleys and belt. The vibration is still there with the belt removed.
Exhaust manifold gaskets
Exhaust hangers, There is no contact of the exhaust system on the frame and no leaks.
Engine runs smooth and accelerates very well. All 8 cylinders are at 150psi. The coilpacks check out at .6 ohms
primary and 7K ohms secondary. No MIss! No codes have been thrown.
The vibration seemed worse at the Cats. I replaced the Y-pipe assy. The vibration got worse!
I can feel the vibration in the body, but not on the engine.
I cannot isolate it whith a stethoscope. There is no unusual noise in the engine.
I have spent hours researching this. I have searched the internet and have run out of search strings. I have talked
with several tech support people at different companies to see if someone has this problem in their database. NoLuck! My favorite response: "I have no idea"
I'm stuck and need some help.