Yes I think it is electrical. Astro's have tremendously high voltage from the ignition coil to the spark plugs. This high voltage will eventually "find" a path to ground. Have you ever had your cowling off? It is the engine cover underneath the drink holders. There are 2 #27 torx bits on each side under side caps and 2 13millimeter nuts on the floor. Then you can pull out the glovebox/drink holder assy enough to unplug the cigarette lighter power plug. Then you just have 2 large flatblade screwdriver bolts on the top of the cowling on each side.
Anyway, the ignition coil wire to the top of the distributor cap often "leans" against a steel engine crossmember. It eventually "punches through" the high voltage and your high voltage does not get to the spark plugs. I had been stranded by this problem several times. I now route the coil wire away from anything metal between the ignition coil and the distributor cap. I also wrap the coil wire with 3/8 inch plastic spiral band and cover that with half inch split loom. If you don't know what spiral band or split loom is, ask any electronic supply store.
Astro's EAT ignition connection components. I replace my spark plugs (ONLY Autolite Double Platinum), ignition wires, distributor cap (no cheap brands like Valuecraft or Duralast, only TRW, Sorensen or quality name brand), distributor rotor every year or 2. I have had to drive my Astro's 50,000 a year for 12 years to do service work.
Where your coil wire leans against a steel crossmember, you will be able to see tiny pin holes where the high voltage "punched through".
Thursday, October 16th, 2008 AT 9:04 PM