Keep a Sleeping Bag in the Car incase you stall somewhere where, where it is Cold. Some food for emergency use that will not freeze like Penuts or Trail mix or Granola Bars.

Matches and a Good Pocket Knife. Targent and Walmart sell the real Swiss Army knives at a resonable price.

Extra Glow Plugs and that hard to find Injector Fuel Return hose. I saw the Duct Tape but I do not recall any Wire steel wire tie up exhaust pipes and some electrical wire.

While I have bought mine from various stores; Harbor Freight sells an less than $10 12 volt Tire Inflation Pump. I have one of those Inflation Pumps in each Car.
There has been several times in my life where having a Tire Inflation Pump (I carried a manual one before the cheap electric ones came out) have allowed me to drive home and not have to ruin my clothing taking off a tire on the road sid.

Two 1 foot square pieces of 3/4 inch Plywood nailed, glued, or screwed togeteher to put under your Jack in case you pull off into the Dirt to do a tire change (at least 2 Wheel Chocks to block the Wheels).
In fact the Billinstin type Jack can be unstable. You might think about also bringing another type of Jack with you and some Plywood of the correct size to go under it.

Something to lay on if you have to get under the car; could even be some big gree Trash Bags (hand to have along any way, cut holes in it and you have a rain coat).

A Tubless Steel Belted Tire Repair kit (plugs) is also handey. Ofter you can pull the object out and insert the plug in the Tire while it is still on the Vehicle.

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84 300D, 82 Volvo 244Gl Diesel