My wifes 05 Limited has had some odd stuff going on lately. Car has 130k on the odo. My problem is I'm 500 miles away and am going on her descriptions of the problem and what 2 repair shops have found. It's had various drivability problems for several months. Hesitation when leaving from a stop, nearly stalling when decelerating (like when slowing down an offramp). First shop did plugs, catalytic convertor(!?) and an O2 sensor. Still had problems. Talking on the phone with my wife made me think TPS. I ordered one and a friend installed it for her. Ran better for a while. Hesitation on acceleration from a stop was much better but shortly the stalling came back and all this time an on/off vibration that sounds like a driveline vibration to me. My brother in law found only a SLIGHT wear on the right side inner CV joint.
I took it to a different shop and he couldn't find any bad joints and said the wear in the CV joint shouldn't be a problem. He found a VERY slight amount of "dust" around the inner seal for the RF wheel bearing so we changed it "just because". When he was test driving it he managed to induce a misfire on cyls 1,3 and 5. He found a TSB that referenced loose valve seats as the problem
and found comments that led us to believe that might be the problem. I read the same on this forum. A week ago I said it can't hurt to pour in some inj cleaner so my wife dumped a bottle in Sunday night, a week ago. Next morning the engine started normal and has run fine since then. Now the vibration
is there by itself. It comes in between 40-50 mph steady state or coasting. It sounds like a worn driveline component to me, going eccentric at certain speeds (trans output yoke)? The car has NO offroad use. We bought it for the AWD capability in inclement weather. It's driven easy and maintained. Could the vibration be the loose valve seat problem that is speed sensitive (harmonics) or just a hard to find loose joint in the driveline? Any thoughts?

Have the u joints ever been replaced? If the vibration is felt in the seat it is most likely some thing in the rear drive line, also check the all rubber components on the rear.

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2005 CRD Limited

When it starts vibrating, put it in neutral, if it stops when RPM lowers then possibly engine related, if its still there it's the rear U joint. Unfortunately you have to remove it to check it, the "feel for the hot end cap/look for play" route does not always work, ask me how I know

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2006 KJ CRD, Dark Khaki, 2nd gen fuel filter head, Fumoto oil drain, new front & rear discs/pads, rear shelf, 156,490 when written off, 1st November 2023

1943 GPW, British Army Rebuild, British Airborne Modifications.

Randy B; U joints have never been replaced but I have checked them earlier in the year and saw NO sign at all of a bad one. I know that can be tricky though.

Slasher; Good idea on the "put it in neutral". If I was driving it I would probably do that, but, like I said, being 500 miles away from home, the obvious doesn't aways come to mind. I'll have my wife try that tomorrow if it happens.