Toyota Repair: 4-Runner failed to start, toyota 4 runner, intermittent problems

Question
Hey Ted --Thanks again for the help on a previous question.  New question:  I have a 1990 Toyota 4-Runner(V6) The other morning it failed to start after sitting all night.  It turned over fine but no start.  My dealer said it failed to start when they picked it up but then thry could not get it to not start.  They checked the distributor (I replaced cap and rotor 1 year ago).  Checked all wiring harnesses.Checked coil(ignitor) and coil wire. All with no result.  Since then it has not failed to start.  My problem is I do a lot of off off road driving and I will be in trouble if it fails to start.  If you have any advice please let me know.  Thanks again for your time.--Jim


Answer
Since it is starting now it's pretty hard to diagnose for a problem, I would assume that at the time it did not start that the engine either lost fuel pressure(possible fuel pump problem)or the engine lost spark to the spark plugs, the latter being the more common, usually igniters don't fail intermittently, distributors can, the pickup coils and rpm signal generator coil can give intermittent problems especially with temperature changes which can change their resistance, distributors are not cheap and I'm not 100% sure thats the problem but that's about all the input I have at this time other than to wait until it happens more often and long enough so the mechanic can check it under the no start condition.