1995 Jeep Grand Cherokee Laredo V6. Runs great but while driving engine will shut off (speed/distance travelled does not seem to matter.) Lights, radio, battery are fine. Car will not start, although cranks great. If I wait for about 3 to 10 minutes it will start right up and drives fine, however after an indeterminate amount of time, engine will shut off again. Repeat steps above. Sometimes does it 3 to 4 times a day, sometimes not for a few days. Mechanics are baffled. No warning as to when it shuts off. No sputtering, hiccupping or anything. Engine just shuts off. At my wits end. Want it fixed but can’t seem to get it fixed. HELP!!
From what you describe, the first thing to focus on is either a faulty crankshaft position sensor or a faulty ignition module. Either of these components can become heat sensitive to where they can cause the engine to turn off as someone turned off the ignition switch. Then if you wait long enough, the component cools down enough where it functions again.
The problem with diagnosing this type of problem is, it has to occur at the time of diagnostics. Because if it doesn’t, nothing appears to be wrong.
Tester
Swap the Automatic Shut Down (ASD) relay with the horn relay. They are the same type.
Here it is shown in Fig. 33: http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800a9de9