Does it happen when car is warm, or cold? any patterns observable as to when the no start happens?
A few quick notes, but not exhaustive:
-CPS generally gets temperamental when engine is hot, ..but not always, --An easy way to observe if it may be the CPS is watch to see if the tach bounces a bit when cranking...
--Fuel pump can be heard "priming" if you turn the key to start, but not ignition. Generally if you hear the pump buzz and prime you can expect the fuel pump is ok.
I would start with these observations. cold or hot engine, fuel pump priming noise, watch tach during the no starts.
Also, if it no starts, when does it start up next? soon, or much later? do you do anything to get it started again? is it no start on first two cranks but then a start on the third?
Lastly, are you located somewhere where temps have changed significantly from winter to spring?
I dont mean to barrage you with questions!
. just this info might lead to the cause 
hope this helps and that some more info can be gleaned from these observations that will help quickly diagnose
good luck!
A few quick notes, but not exhaustive:
-CPS generally gets temperamental when engine is hot, ..but not always, --An easy way to observe if it may be the CPS is watch to see if the tach bounces a bit when cranking...
--Fuel pump can be heard "priming" if you turn the key to start, but not ignition. Generally if you hear the pump buzz and prime you can expect the fuel pump is ok.
I would start with these observations. cold or hot engine, fuel pump priming noise, watch tach during the no starts.
Also, if it no starts, when does it start up next? soon, or much later? do you do anything to get it started again? is it no start on first two cranks but then a start on the third?
Lastly, are you located somewhere where temps have changed significantly from winter to spring?
I dont mean to barrage you with questions!
hope this helps and that some more info can be gleaned from these observations that will help quickly diagnose
good luck!