Check engine light

What does it mean when the engine light on a Cadillac CTS 3.6 blinks 5 times?

Engine Mechanical problem
2005 Cadillac CTS 6 cyl Automatic 69000 miles

what does 6 cyl not running means?And is it exp to repair

Had a very slight miss when under moderate acceleration. Ran a scanner and came up with cyl 3 misfire. I replace all the plugs put the car back together, hit the key and the car ran like crap. Would barely run. Also heard something "rattling". I hit the gas and it sounded like a nut or something may have fell into intake but I did not ccompletely take the intake off. I only moved it to the left and right as I needed. Also I did not end up missing any bolts or anything so I do not believe anything fell into my motor. Anyway I tore the car apart 3 more times taking every plug out and finally the knocking stopped. The car how ever is still running aweful. I have 2 coils on order right now hoping it may fix the problem but I'm not so sure. The knocking/rattling sound has me scared because I've heard horror stories about timing problems. I haven't ran my car low on oil. Check it pretty often. Also I don't understand how it could run fine then with new plugs it runs like crap. Also the first time I tore it back down after the miss started I put old plugs back in it still missed something aweful. Please any advice would be amazing. Thanks - Brandon

Thank you for the reply. I took the car to my local auto parts store and had it scanned again after unplugging the battery all night. 16 codes! The guy said that the computer has to "relearn" or something and he unplugged it before I could write them down. I guess he was in a hurry. I did see the random misfire code along with every cylinder misfiring this time. I did absolutely nothing but put plugs in. I cannot believe the car of my dreams is cropping out on me. I owe about double what it Is worth too. Is there a chance something really bad has happened? I'm calling the car lot where I got it in the morning since the nearest dealership is 50+ miles away. Any thing that you can think of that I should tell them to look at? I'm 99 percent sure I did nothing that could lead to it jumping time or nothing like that. Like I said I check my oil pretty much once a week. All I did was drive home from work which is right at 50 miles and pull into the garage. No noises before changing them. Put it together and cranked her up and bam. I don't understand how I could go from 2 codes to 16 just by unplugging the battery.

Yea I didn't really think he knew much. I will get it scanned again this evening to see what codes come up and I will post them all. I hope it's not a timing issue. What codes would show if it was something to do with the valves or timing? Also I'm not the original owner. Is there any tsb or recalls my car may qualify for? Is not under warranty either.

Ok. By what I'm telling you what would you guess is wrong? The whole thing about changing plugs leading to this has me pretty angry with it. Is there a way for someone to check and see if anything is up with the valves?

Ok didn't do the compression test because I really don't think it's an internal problem. I went ahead and bought some double platinum autolite plugs and installed those and it still didn't help. Hooked it up to scan for codes and it came up as random misfire and no. 1 2 and 3 cylinders are misfiring. Brand new plugs. They have 10 miles on them now. I gapped them to .050 because that is what the guy told me to do. I'm lost. Taking to the car lot I hot it from to let them check it out. Any info you guys could give me sound be appreciated. The auto parts guy said it could be where I unhooked the battery and it could possibly be a cam or crank sensor. I have no knowledge about these engines other than what I've read over the last 2 months. Thanks again! And we're you recommending that I should do the compression test? Or did you mean that it would tell me if my valves were bent?

My cts check engine light came on and it was placed on a computer and scan and I was told that there was no codes. Then it was good for a few days and it came on again, then a few days later it cut off again and it's been doing ever since, can you guys help?

I got two codes p0420 &p0430 let me know what you think.

Am still waiting on an answer please.

When I fill my car with gas the DIC displays the estimated amount of miles that it can have with the gas was put in, but for some reason the miles range changes significantly lower with only the passing of a few miles. I.E. The DIC would read 186 miles range, then after driving for about 3 to 4 miles it would read 96 miles range. Why would this be? I've recently had the ECM re-programmed by the dealer but I have had a check engine light reading that shows the catalytic converter being faulty and I also have custom wheels if that would make any difference.