1987 Ford Ranger problems

Haven't had it happen to me personally; but a vehicle computer does sometimes fail. The 2.9L 's computer has an excellent record for longevity.... but shit does happen. The TFI ignition module is a known "hi-fail" item; going there first was not a bad idea.

You went thru the "substitution troubleshooting" maneuvers well though.

Others may disagree on the fine points; but here's the guidelines:

Substitution Troubleshooting Guide:

1) Do the best you can with the tools and trainimg you have to get the problem isolated to as few parts (that you don't have on hand) as possible. You've aleady gone thru those; right?

2) See which ones you can borrow; try those first. If no luck there >>

3) Now you get to make decisions! There's three choices to balance a) which is cheaper b) which is easier to replace c) which is locally available

4) If this didn't fix it; decide again.

The "no spark" problem choice of the TFI is 3 a/b/c for most folks as its reasonably easy to replace; not badly expensive; and widely stocked.

It is very common for the green wire that plus into the coil to go bad at the connection to the coil. This will produce exactly the symptoms you suggested. I would check that before the computer is installed. I have seen this a number of times.