Join Date: Feb 2009
Location: Northeastern BC
Agree with Blue Oval. I just wanted to add that you might want to inspect all the ignition system connections, particularly on the high voltage side. Over the years something may have come slightly unplugged.
You don't necessarily need a solid physical connection for a high voltage circuit to work -- most of the time. But when you start jostling things around, it'll fail.
My own example of that, is many years ago I drove my old AMC Concord all the way from Barrie, down the 400, down Yonge St., and when I made a left turn off Yonge near Lawrence, to get into my side street, the engine completely conked out. When I checked under the hood, the last shards of the distributor cap were dangling from the coil and spark plug wires above the rotor. I had forgotten to screw down the cap earlier in the day, and the car made it all that distance (in an almost straight line) from Barrie, with no problem. The first sharp turn I made, and the dangling distribor cap hit the spinning rotor and smashed it.
Obviously, the Ranger 4.0 doesn't have a distributor cap. I'm just trying to illustrate that things can run fine with the ignition high voltage, because the current will jump an open air gap (that's how mechanical distributors and your sparkplugs work). But if you move things around, like turning a corner, or going up or down a steep hill, wires can move enough to open something, causing you to lose spark. As soon as you level out, the connection re-establishes itself, and everything seems like it's back to normal.
Like Blue Oval said, definitely check your coil pack. Wiggle the related parts of the wiring harness around, and the various high voltage wires while it's idling, to see if you can reproduce the problem and narrow it down. Disconnect the various cables, check that the connections are clean and free of oxidation, and replug them.
If it's an electrical problem you need a bit of patience and persistence, and you have to be methodical.
If Princess Auto were a real girl, I'd ask her to marry me.