If you do wind up replacing the GPs, try to get a GP hole reamer tool to get the carbon out of the prechambers. Run that down in there for each plug hole before you install the new plug. Use anti-seize on the plug threads when installing a new plug.

If you can't get the reamer tool, start the car, warm it up a little and do the plugs one at a time. When you remove one plug, start the engine, rev it to like 3500 or 4000 for a few seconds. That will blow the carbon and crap out of the GP hole. Install new GP and do the same for each. I had to do this on my #5 because I could not get the reamer in the hole due to the oil filter housing in the way. I tried the reamer again after running with no GP in that hole and it slid right in. Nothing to clean out.

Great! I guess there are a few more aftermarket items available for these sweethearts now, that weren't around when I was driving and maintaining them.

Let us know how it all works out for you.

You describe classic symptoms of one or two bad glow plugs. Maybe not a problem in warm weather but definately a problem when it gets chilly.

Some engines are really touchy with even just one glow plug bad. I had a diesel once that absolutly refused to come to life cold with just one open glow plug. Yet otherwise seemed to be in good condition enginewise. It made little sense at the time but it was what it was.

Adjusting valves or at least checking them for decent clearances is very important. Many of these cars have gone tremendous amounts of milage since the last time done. The manufacturere recommends every fifteen thousand miles.