Saw your post. Don't know a lot about this but have a little experience
with the VM 2.5. Did your local garages try anything or have any theories?
When the glow plugs don't heat and you turn the starter over anyway to
"fire it up", the engine is sure to rattle and jump around because
everything is cold. Same thing as if you push started it, which I have
done a lot.
It could be an inadequate battery/charging system or a bad glow plug
relay. Since you get the problem also sometimes while on the road, the
latter is unlikely.
How old is your battery? The glow plug system runs at 12v unlike some
other diesels which use 7-11v and it needs a lot of electrical power. I
bought 75amp batteries and never had one last more than a year and a
half. Make sure your alternator is giving you 14volts. Clean the battery terminals.
Clean and scrape the ground connection at the engine block.
You may also have an air leak in the fuel system, which causes problems
at starting and maybe intermittently when running. Sometimes the
o-ring on the fuel filter can leak. Take it off, clean the o-ring, and make
sure it seals smoothly. If it is time to change the fuel filter (about every
20,000km), replace it. Check the fuel lines to the injectors and replace
any that are kinked or damaged.
If you don't have a Factory Service manual, you can access one for the
VM engine on this page. It has troubleshooting helps.
It is in the Cherokee/1996-2001/ "Engine" section beginning at page 121,
after the two gasoline engines' info. The 1995 should not be much
different than 96+, except yours does not have the OBDII diagnostic