I have a 1991 Chevy S10 2.5 L4, do you have a wiring diagram for the distributor cap and spark plug wires?

It can be faulty or dirty spark plug itselfd.Also for reference get the fuel level checked.Is the fuel tank is empty or near to empty.
Try cleaning the spark plugs and then see if that is helpin.On some cases the black carbon layer gets collected on the spark plugs and that causes the problem,so cleaning the plugs help.But if its not helping,then spark plug has to be replaced.Spark plugs get power from ignition coil to ignite sparks.If ignitioncoils are faulty then also there will no spark.--------------

To troubleshot and confirm the issue,i suggest you to go through the help links provided below,check the procedure and it will help you to confirm the issue in your case.
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Click the link below:------

Car cranks, has spark but will not ?

http://howtobyme.blogspot.com/2011/12/car-crankshas-spark-but-will-not-start.html

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The spark plug firing order for car?

http://schematicsdiagram.blogspot.com/2011/06/spark-plug-firing-order-for-car.html

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How to Replace Spark Plugs?

http://schematicsdiagram.blogspot.com/2011/07/how-to-replace-spark-plugs.html

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How to Perform a Basic Engine Tune Up-Spark Plug and Wire Change

http://schematicsdiagram.blogspot.com/2011/08/how-to-perform-basic-engine-tune-up_01.html

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Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

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How does the spark plug wire go on the distributor cap in 1991 Mitsubishi Mighty?

http://schematicsdiagram.blogspot.com/2011/12/how-does-spark-plug-wires-go-on.html

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No spark on 2008 Chevy Avalanche?

http://schematicsdiagram.blogspot.in/2012/04/no-spark-on-2008-chevy-avalanche.html

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How does the spark plug wire go on the distributor cap in 1985 Pontiac sunbird?

http://schematicsdiagram.blogspot.com/2011/12/how-does-spark-plug-wire-go-on.html

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Ford Plug Wires Not Coming out?

http://whoisbyme.blogspot.in/2012/06/ford-plug-wires-not-coming-out.html

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Ford explorer has no spark?

http://schematicsdiagram.blogspot.com/2011/12/ford-explorer-has-no-spark.html

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Chevy impala spark plug firing order diagrams?

http://technoanswers.blogspot.in/2012/02/chevy-impala-spark-plug-firing-order.html

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How to gap spark plug on Chevy Impala?

http://technoanswers.blogspot.in/2012/02/how-to-gap-spark-plug-on-chevy-impala.html

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Spark plug Replacing for chevy impala?

http://technoanswers.blogspot.in/2012/02/spark-plug-replacing-for-chevy-impala.html

Chevy s-10 blazer 4.3l Spark Plug Firing Order?

http://howtobyme.blogspot.com/2011/12/chevy-s-10-blazer-43l-spark-plug-firing.html

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1982 dodge rampage Spark plugs Firing Order Diagram?

http://schematicsdiagram.blogspot.com/2011/12/1982-dodge-rampage-spark-plug-firing.html

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2006 Suzuki Forenza Spark plug Firing Order Diagram?

http://schematicsdiagram.blogspot.com/2011/12/2006-suzuki-forenza-spark-plug-firing.html

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1983 Ford Ranger Spark plug firing order?

http://schematicsdiagram.blogspot.com/2011/12/1983-ford-ranger-spark-plug-firing.html

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Firing Order for 1991 Lexus ES 250?

http://schematicsdiagram.blogspot.com/2011/12/firing-order-for-1991-lexus-es-250.html

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Firing order for 1992 Chevrolet 5.0 engine?

http://schematicsdiagram.blogspot.com/2011/12/firing-order-for-1992-chevrolet-50.html

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How to identify number one spark plug on the distributor cap?

http://schematicsdiagram.blogspot.com/2011/12/how-to-identify-number-one-spark-plug.html

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How to remove rear spark plugs on 1991 Buick Regal?

http://howtobyme.blogspot.in/2012/02/how-to-remove-rear-spark-plugs-on-1991.html

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These details will help.

Thanks.

We do not have wiring digrams here but you can access them and all the factory service information here for a small fee.

For spark plug problem,click the help links provided below :---Car has no spark?http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html
------------How to Replace Spark Plugs?http://schematicsdiagram.blogspot.com/2011/07/how-to-replace-spark-plugs.html
-------------Car cranks, has spark but will not start?

http://howtobyme.blogspot.com/2011/12/car-crankshas-spark-but-will-not-start.html

------------------------
The spark plug firing order for car?http://schematicsdiagram.blogspot.com/2011/06/spark-plug-firing-order-for-car.html
----------How to gap spark plug ?http://technoanswers.blogspot.in/2012/02/how-to-gap-spark-plug-on-chevy-impala.html-----------Spark plug Replacing for?http://technoanswers.blogspot.in/2012/02/spark-plug-replacing-for-chevy-impala.html
-----------How to identify number one spark plug on the distributor cap?http://schematicsdiagram.blogspot.com/2011/12/how-to-identify-number-one-spark-plug.html
---------How does the spark plug wire go on the distributor cap?http://schematicsdiagram.blogspot.com/2011/12/how-does-spark-plug-wires-go-on.html
---------Spark plug Firing Order Diagram?http://schematicsdiagram.blogspot.com/2011/12/2006-suzuki-forenza-spark-plug-firing.html
-----------This will help.Thanks.

For spark plug problem, click the help links provided below: ---
Car has no spark?

http://schematicsdiagram.blogspot.com/2011/06/car-has-no-spark.html

------------
How to Replace Spark Plugs?

http://schematicsdiagram.blogspot.com/2011/07/how-to-replace-spark-plugs.html

-------------
Car cranks, has spark but will not start?

http://howtobyme.blogspot.com/2011/12/car-crankshas-spark-but-will-not-start.html

------------------------
The spark plug firing order for car?

http://schematicsdiagram.blogspot.com/2011/06/spark-plug-firing-order-for-car.html

----------
How to gap spark plug ? http://technoanswers.blogspot.in/2012/02/how-to-gap-spark-plug-on-chevy-impala.html

-----------
Spark plug Replacing for?

http://technoanswers.blogspot.in/2012/02/spark-plug-replacing-for-chevy-impala.html

-----------
How to identify number one spark plug on the distributor cap?

http://schematicsdiagram.blogspot.com/2011/12/how-to-identify-number-one-spark-plug.html

---------
How does the spark plug wire go on the distributor cap?

http://schematicsdiagram.blogspot.com/2011/12/how-does-spark-plug-wires-go-on.html

---------
Spark plug Firing Order Diagram?

http://schematicsdiagram.blogspot.com/2011/12/2006-suzuki-forenza-spark-plug-firing.html

-----------

This will help.

Thanks.

In the diagram below #1 plug wire is the all white dot on the distributor cap at the bottom 6 Oclock position (slightly to right), the firing order goes in the clockwise direction as the arrow indicates around the cap.

Fire order
1-3-4-2

Cylinder #1 will be the one closes to the fan belts and so on 1-2-3-4, on the distributor cap there should be a # 1 stamped on it, put cylinder # 1 spark plug wire on that one, install spark plug wire in firing order clockwise on the cap, the cap some time's might even have the firing order on it.

POSSIBLE distributor cap and rotor spark plug wires

Here are two links which will show you what you need... it depends on the engine you have.
2.5 liter DOHC V-6
http://autorepair.about.com/library/firing_orders/bl-fo-6767.htm

2.0 liter DOHC L4
http://autorepair.about.com/library/firing_orders/bl-fo-6766.htm

Hi
Here is a diagram.