Engine light on ,reading was P0455

• Fuel Smell. One of the most obvious signs that you are facing an EVAP leak is the smell of fuel. ...
• Check Engine Light. One of the first symptoms of an EVAP leak is also the presence of the Check Engine Light. ...
• Poor Engine Performance. ...
• Hard Start. ...
• Failed Emissions Test.

https://www.way.com/blog/p0455-code-meaning-symptoms-causes-and-fixes/

A flashing or blinking check engine light indicates a severe engine misfire , which will damage your catalytic converter .

Flashing check engine light CarMD

P0455 Kia EVAP Emission System Leak Detected Large Leak

Bad ignition module often will not set a code for itself. Hard to diagnose due to being so random. Also just possible tach feed wire is shorting somewhere, coming and going.

What is the year, make and model?
How many miles on it?

You should know that when the check engine light flashes ENGINE DAMAGE can occur!!!

OK!... check engine lignt came on AGAIN!...what code(s) were there? (20 miles doesn't tell me anything).

It may just be a sensor failing, or even as simple as a loose gas cap. You need to get it scanned to see what the error is that the computer found. (Some auto parts stores will do this for free, but they don't give a lot of information. Try that, if no luck, try a good garage.)

MAKE SURE YOUR ENGINE IS WELL TUNED. MAKE SURE TURBO IS WORKING NO RESTRICTED EXHAUST..ALL PLUGS AND WIRES ARE GOOD.SOUND LIKE TRANSMISSION SLIPPING.HAVE TRANSMISSION PRESSURE TESTED.IF FLUID LEVEL GOOD AND TRANSMISSION FILTER NOT STOPPED UP.PROBLEM COULD BE TRANSMISSION SHIFT VALVES OR TRANSMISSION PUMP OUT PUT PRESSURE TOO LOW.

if you live near and auto zone have them read the code. my voyager had the same problem around 60 thousand and it turned out that the computer crapped out and had to be replaced not cheap!!! but i hope for you its something simple let me know what the code says from auto zone if you have one near you thanks

i have 56,000 miles and have the same thing....The dealer has told me it is normal on that motor many times.

Check out this thread and take your Caddy for a couple of Wide Open Throttle runs on the Interstate. Clears out the carbon buildup on the rings that is causing oil blowby.

http://townhall-talk.edmunds.com/direct/view/.f1078f6/0