When the problem occurs, if it cranks good but won't start, have a helper crank it, while you check for spark at the plugs. If you have spark everywhere, use a gage and check fuel pressure. Some of the national brand autostores used to loan out a fuel pressure gage.
To check for spark, take a spark plug wire loose, use a spark tester or known good spark plug in the boot, ground/touch the metal part of tester to metal part of engine, engine cranking, watch for spark.
With intermittent issues, you have to test when problem is ongoing. Any applicable trouble codes? To check for codes, yourself, at the least, you need an obd2 code reader.
Please consider a to help us answer more questions.
Thursday, June 23rd, 2011 AT 7:14 PM