Engine vibration with a 1992 crown victoria

SOURCE: Vibration

vw's have manifold vacume issues if camshaft timing is out by even the slightest amount causing vibration at lower idle speeds . the camshaft sproket floats on the cam did your mechanic replace the cam seal if so and he did not have the special tools its a good chance thats your problem i encountered this issue in a audi a4 v6 i got the tools and found a 3 deg difference between banks my customer had also had all engine mounts replaced hope this sheds some light for you

SOURCE: 2003 subaru outback engine vibration in gear

Did you recently replace the axles on the vehicle? This problem commonly occurs in Subarus when you replace the axles with non-OEM parts. The only fix seems to be to swap out the axles for OEM parts. Search the forums at subaruoutback.org for many stories of the same condition and some theories on why non-OEM axles cause the problem.

SOURCE: 94Metro Has a bad vibration at idle, gets worse in gear stopped

check all motor mounts first. if they are ok then check to make sure all cylenders are firing. try pulling one plug wire off the spark plug and see if the engine changes sound or anything. if it does, put the wire right back on then move to the next one and repete. if you pull one and it does not change then that plug is not firing. could be caused by a crack in the porcelian in the plug or bad plug wire connection or bad wire

SOURCE: Vibration when in gear, and stalling.

The problem is the torque converter solenoid. I had it happen on my 94 Cavalier a few years back and was a cheap fix at the local car mechanic. What happens is the transmission warms up and hits a certain speed where the solenoid engages, but then it sticks and won't disengage until it cools down sufficiently. When it sticks, it causes the car to shake when slowing down and will snub out the engine if you come to a stop.

SOURCE: 2000 Discover TD5 Auto harsh vibration under power at 2000 -2500

The "lift off and it goes away" is the clue I feel. This eliminates engine out of balance issues and points squarely to fueling issues. I would say try a compression test (always a good first start before you try much else) but with plenty of power and no vibration except in the range, probably not a compression issue. So, what's left? Fuel or air is the answer. Check air inlet path is from air filter to turbo and (more importantly) from turbo to intake manifold. Check wastegate on turbo is OK - disconnect the wastegate (it's bolted on to the turbo) hose, then **** on the wastegate hose, you should feel resistance. If not wastegate aneroid has perforated. At this point, I suggest taking it to a LR dealer and get them to pull all the engine codes. If all OK, next step is injectors. It's a common rail diesel and removal is a bit tricky, but if you pull them out, you will often be able to see a single injector with all the carbon deposits around it. If all injectors look the same, suggest that at this point you need to take them to a diesel specialist for testing and calibrating. This process usually cures 70% of diesel misfire problems. The other 30% really requires specialist knowledge of your vehicle's engine.