Hi Discoverytd5es, If it's any help, mine vibrates at those revs and always has done. I think I read this happens a lot. It hasn't got worse and is not a real problem. I also checked out the same stuff as you did. Once had a Renault 17 with a really annoying engine vibration that came in at exactly 70 mph! Took it to garage which simply said "yeah, they all do it!" (This was back in the 80s.)
5 cylinder engines must be pigs to balance. Have you checked or replaced the engine mounts? Obvious, I know! My truck has done 150k plus by the way. There are far more annoying things that will need sorting out on a TD5.
I have just had to remove the (warped) exhaust manifold and get it reground. That was the easiest part! The pig was sorting out the broken studs. If you can, get to it NOW remove the nuts, get it ground flat, enlarge the holes in the manifold to give it room to move if necessary and then put it back on. Cylinders 1 & 5 need drilling 2 mm bigger, cyls 2 & 4 1 mm bigger. There are kits on the market you can get to sort this out which give you longer studs and spacer washer-type things. I'd also recommend testing and/or changing the MAF. Mine drinks the diesel it's an auto, so yes to be expected, but even so! When I got it I discovered it had been chipped, and was thus more economical, but sadly, when taking the red plug off the ECU (ECM) I dropped it and it would not work again, so I had to get another. DO NOT DO THIS!
5 cylinder engines must be pigs to balance. Have you checked or replaced the engine mounts? Obvious, I know! My truck has done 150k plus by the way. There are far more annoying things that will need sorting out on a TD5.
I have just had to remove the (warped) exhaust manifold and get it reground. That was the easiest part! The pig was sorting out the broken studs. If you can, get to it NOW remove the nuts, get it ground flat, enlarge the holes in the manifold to give it room to move if necessary and then put it back on. Cylinders 1 & 5 need drilling 2 mm bigger, cyls 2 & 4 1 mm bigger. There are kits on the market you can get to sort this out which give you longer studs and spacer washer-type things. I'd also recommend testing and/or changing the MAF. Mine drinks the diesel it's an auto, so yes to be expected, but even so! When I got it I discovered it had been chipped, and was thus more economical, but sadly, when taking the red plug off the ECU (ECM) I dropped it and it would not work again, so I had to get another. DO NOT DO THIS!