1999 Ford Explorer will crank, but not start

[bobrubino@msn.co]

Have a 1999 Ford Explorer with a 4.0 liter SOHC engine, 129K miles on vehicle. Yesterday morning it would crank easily but it would not start. Checked fuel rail - had fuel and it was pressurized. No problems before this non-start. Ran OBD code tester tests - response: No communication with ECM. Checked and found I am not getting a spark at the spark plug. Checked fuses - all good and had voltage at them.
Any suggestions? With a 'no communication' message from two different OBD testers I am leaning toward a bad ECM. Is there anything else to check before spending over $300 for a new ECM (local auot parts supplier has no way to test the old ECM).

 

[shadowless127]

check and make sure the harness from the ECM is in good shape, and the plug is firmly attached.

 

[bobrubino@msn.co]

Crazy thing is I took the whole ECM out of the vehicle opened the unit to see if there was any visible problems. Seeing none I put it back in, visually checked the cable and reattached it. Vehicle started. Ran the code checker tests again - unit ran the tests and reported no performance code problems - reported a few minor codes but none related to engine. Will see if it starts up tomorrow morning. Hope it was a cabling problem and hope it is fixed.