Dodge Repair: 96 Diodge Caravan hard start condition-This is a challenge!, spark plug wire, dodge caravan

Question
96 Dodge Caravan 3.3l 196,000 miles. hard start when below 60 degrees.  You can crank the engine for about 4 min and it will finally start.  Once started you can turn it off right away and it will start up again just fine. Engine runs just fine once it is started. There is good spark I used a screw driver in the end of a spark plug wire to ark to the manifold.  we have replaced both o2 sensors and the fuel filter.  just a note you can squirt starting fluid in the throttle body intake and the van will start right up?  I am at a loss to figure this out and with colder weather already here is is getting worse.  Any suggestions will be of help!  Thanks in advance.

Answer
fuel pump................fuel pumps serve two purposes;
1-fuel delivery to the engine

2-when the engine is not running the pump will hold "head pressure" in the fuel line so that there is fuel readily available to crank the vehicle  How many times have you heard the "whirring" sound when you switch your car to the on position ?? That is the fuel pump turning on and pressurizing the line

If you wanted to verify this, take your vehicle to a shop and have a fuel pressure test run to validate your pump is up to par. You may even have a bad ground wire in the pump, physics being physics, if the ground is broken or almost broken the colder temps would cause this wire to contract thus opening up the gap and creating inability to operate the pump efficiently (I have seen this in mid 80's GM cars)

Good luck