I have a 1995 chev lumina 3.1 engine. The car always starts and runs fine when cold. After driving the car for a while and the engine is hot it will restart right away after turning off. BUT if the car sits for 15 minutes or more after shutting off it will not restart. Fuel filter ok fuel pump running ok.It will try to start but sputters out like all cylinders arent firing. Once it cools down enough it starts fine again????

either drive train or engine compression , get the cylinder compressions checked as the easiest place to start , if ok check for the air intake and vacuum systems and then the drive train good luck

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------

1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------

1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------

2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------

Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------

Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

-----------

Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------

Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------

Car won't start when cold?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

===========

These details will help.

Thanks.

HOT/WARM START ISSUE

Its a hot start issue.

Can be related to low fuel pressure or problem with crank sensor.

Also it can be weak battery or starter.

But possibilities are to be inspected to confirm what exactly it is.------

To troubleshoot and confirm the issue,i suggest you refer few solved help links with similar types of problem like yours:------

Click the link below:------

1991 Toyota Trecel: Engine Starts fine but dies when gets Warm?

http://whatisbyme.blogspot.in/2012/05/1991-toyota-trecel-engine-starts-fine.html

-------------

1994 Toyota Pickup: Starts fine but dies in few seconds?

http://howtobyme.blogspot.in/2012/05/1994-toyota-pickup-starts-fine-but-dies.html

------------

1995 Lexus LS400: Running Hot?

http://whatisbyme.blogspot.in/2012/05/1995-lexus-ls400-running-hot.html

------------

2002 Toyota Camry: Puff of Blue or White Smoke while Starting?

http://whatisbyme.blogspot.in/2012/05/2002-toyota-camry-puff-of-blue-or-white.html

------------

Multiple problems on car: Car runs hot, A/C blows hot and car starts surging?

http://schematicsdiagram.blogspot.in/2012/04/multiple-problems-on-car-car-runs-hotac.html

--------------

Delay starting on Toyota Prius?

http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

-----------

Honda car will not start intermittently?

http://technoanswers.blogspot.in/2012/02/honda-car-will-not-start-intermittently.html

--------------

Vehicle Starts, Runs and Loses Power

http://whoisbyme.blogspot.in/2012/07/vehicle-startsruns-and-loses-power.html

--------------

Intermittent starting issues on Volvo 760?

http://schematicsdiagram.blogspot.in/2012/02/intermittent-starting-issues-on-volvo.html

-----------

Car starts and cuts off immediately?

http://repairhelpcenter.blogspot.com/2012/01/car-starts-and-cuts-off-immediately.html

-----------

Car won't start when cold?

http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-when-cold.html

===========

These details will help.

Thanks.

selonoid problems most likely on chev.hot start problems since 1955.you can install external starter seloind to correct problem or try and insulate seloind

some common problem in the summer when car get hot over and over the ignition (coil) is affected it will make your car cold run fine but cuts off when hot if occurred look for the coil
if you let car cools down for an hour then it started and work fine until cut off when hot again sure it is coil .

I had a similar problem. Is your temperature gauge pegged to the right as very hot? Or reads always cold, even when hot. If it is a 3100 motor their is a coolant temperature gauge sending unit under the air breather intake that is right next to where you replace the thermostat.

Get a haynes repair manual at a parts dealer, Amazon, or your public library.
On the Chevrolet Lumina, Monte Carlo, & Impala FWD 1995 to 2005 it's under section 3-8 on page 3-6. It goes into great detail, and it's too complicated to explain here. If your sensor is bad, but the wires and fuses are good then the fans won't run.

Your second fan only runs when the air compressor is turning, If your ac compressor is not running then the sensor will not have the passenger fan run.
You have to see if the fan motors are good and then the wiring is good, and no fuses blown. You might blow fuses so have extra blue ones if I remember right. Recheck fuses after testing.

I didnt see it in your list, so I would suggest the O2 sensor, usally found on the exhuast pipe near the engine or on the back of the engine

there are diffrent things that will cause this ,its best to have a reputable shop take a look at it !

When it stops, does it have spark? (crank sensor)

is it an auto choke if so it may not be working some cars have a cold start which is on the inlet manifold and some are in the carbs them self but i think it is not working so that is why it runs rough when cold hope ive helped you