Missing at all speeds

surely the bike is fuel injected, which might mean the fuel pump is playing up , which could be a pressure sensor in the system, you might need to get the computor scanned to see whats faulty

It is 13 years old, and has not been ridden. Probably has crud in the carb, varnish in the tank and fuel lines, cracks in the vacuum lines, etc etc.....

Google Cobra and find their service center. OR you may even find a downloadable manual via Google.

If the bike has been dropped, the stand could easilly be slightly bent.
Put the bike on a paddock stand and take a closer look. It will become obvious as soon as you can get underneath with the stand.
Ride safe.
Nice bike!

If you have changed the air cleaner intake in any way , or the exhaust system in any way , you probably need to put a Power Commander on the cycle. If you have a Power Commander on the already, you need to hook your motorcycle back up to your computer and try a different map for your CDI box. Fuel injected motorcycles are very precisely made. They do not have the ability to compensate for changes you make to the intake and exhaust. By adding a Power Commander, You get the ability to change the fuel injection/power curve to match the changes made to the stock set up. To fix your bike you have to either put your bike back to stock ,or add (or remap) the Power Commander. If your bike is stock and giving you these issues, take it back to the dealer and have the fuel injection system checked out.

Unless an aftermarket device has been installed on your bike, you must take it to a dealer to get the fuel map reworked.

make sure bike has high performance air filter to coincide with the jetting,very important

Check valve clearance, as vlaves wear the gap closes, most riders don't bother to adjust them till they have a problem like this.... By the way the valve may be part of the issue for backfiring while deccerating but Pipes cause this.

The AIS system is usually on the left side of the bike.
Although this is for a Yamaha 1100 custom it should give you an idea what to look for.

Good luck!
Hope this Helps!

HI if this is a bike with carbs then I would highly suggest rejetting them with the after market pipes, if it has injectors then I would recomend checking to see if a power commander is availible for the bike so that you can tune the fuel curve, it will help with the performance as well as your fuel problem