91 wrangler shutting down

Hey guys,
I thought I'd fixed my problem with the new ignition switch replacement, 
But! Today it just shut down going down the raod.  About an hour or so
later 
it cranked fine and ran about seven miles down the road and died again.  I

purchased a crankshaft position sensor and I going to install it next. 
The 
thing I noticed is that when the check engine light comes on when I first 
switch on the key (the way it suppose to) it'll fire right up.  But when
the 
check engine light fails to come on when I switch it on,  even though the 
gages are working, it won't fire up.  Could this be something in the 
computer or what?
 Thanks again in advance for all your help.
Dean
1991 Wragler, 4.0L , 5speed
-- 
Joyce Rigdon  ID #257907
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