Check engine light comes on...and off but mostly on on my jeep cherokee...the scanner show no code

Can be a bad O2 sensor. Check with a scanner which shows live data the 1-1 and 2-1 (upstream) sensors. Good sensors show a rapidly fluctuating voltage from 0.2 to 0.8 V. When the sensor has a steady voltage, then its most probably bad. There is no check engine light and no fault codes set?

The flashing light on your car is telling there is a problem. On some vehicles require a OBD2 code scanner for the diagnosis. Once you know the code, you can most likely repair it yourself. There are fairly easy procedures that most people are capable of repairing.

yeah, you should take a cheap OBD2 code scanner to have a check.

Yes, very much so!!! The fuel filter is often overlooked. They should be changed every 20,000 miles, or less. I would check the air filter also. I changed one last week, that didn't look that old, and the gas coming out of it looked like milk, I did another one on an other, and the gas coming out of that one looked like black ink.

could be a couple of things last time tuned up meaning changed ,spark plugs, wires,fuel filter air filter oil change depending on condesation level put some dry gas in gas tank

Take it to Autozone and get an engine diagnostics done. They have a scanner that will give you the code that is causing your check engine light to come on. you can troubleshoot from there.

coincidence or you have unpluged a sensor around the radiator, air intake etc... check connection or have the code read with a scanner at a garage for minimum fee

You cant adjust it. Your car has a tps sensor " throttle position sensor " and a iac idle air control. these are both on the throttle body. is the check engine light on? The best way to check them is on a scanner at places like auto zone they will let you use one for free. and will help you do it. first check the codes if any then look at live data scroll down till you see tps and look at its values rev the motor up and it should change values are 0% to 100% no throttle to full throttle. at idle it should be 18 to 26 or so. if it doesnt change or its at a high number and no gas is being given then its bad. also look at the iac and see if it changes as well. you can also google the resistence values for each and ohm them out. It does sound like a bad tps. try that first , and the tps is easy to change

A common problem on many of the new cars is that when a person gets gas, they don't tighten up the gas cap. This will turn on the check engine light. Did you get gas recently? Another option is to see what code is stored in the ECU that turned the light on. This is done with a scanner tool. If you do not have a scanner, then have a dealer look at it.