We have a 1999 jeep that all of a sudden does not have any fire to the plugs
I have checked everything that could be the problem will no results
The engine cranks fine .this jeep give no indication the day before it would not start

These are the type of automotive problems I enjoy working on the most. Many of us have been where you are today. Try reading sections A and B below:

https://www.askmehelpdesk.com/cars-t...das-46563.html

Many of the steps are applicable to most any make of car today. Begin by testing all under-dash and under-hood fuses with a test light or multimeter. I can't tell you how many cars I have worked on where the problem was fuse-related. You need to rule that possibility out right from the "get go." Here's how to properly test fuses:

https://www.askmehelpdesk.com/cars-t...tml#post252145

After testing fuses, test for codes. You'll need a scan tool to do this. Stay positive and realize you can solve this problem yourself and learn a ton in the process.

What model Jeep and what engine do you have?

. To verify that the ECM is likely okay, I would test reference voltage between MAP-Baro Sensor's connector (+) and ground, when the ignition switch is turned to ON. It likely should be around 5 volts. I would do the same for the Throttle Position Sensor. Test for voltage to the coil.

. Have AutoZone test the coil for free.

If everything tests okay and there still is no spark, I would suspect the ignition control function, which is part of the Engine Control Computer, is bad or the Crank Position Sensor has failed.