Why would my fourwheeler lose power and stall after running awhile

Try changing plugs maybe

Could be time to replace battery, this is most likely the culprit. These fourwheelers are very picky when it comes to low power. Your starter is also most likely just fine, the clicking you hear is the solenoid on the starter, so your battery has some juice, but not enough amps to turn over the starter. Also If the fourwheeler has sat for a long time then you may just need to charge the battery. The 2007 is most likely fuel inject which uses even more fuel when running and it also has its own computer kind of like a PCM in a car or truck. These all need a good supply of power and the stator which is like an alternator usually needs the help of a fully charged battery to keep everything running properly. Also note, once you get a new battery or charge it in some cases the ATV should run smoother.

Sounds like fuel pump is going bad and needs to be replaced.

Loss of power, but no mention of rough or inability to idle (including stalling). If those additional symptoms are part of the problem, check for a vacuum leak to the intake. Listen for hissing or sucking noises near air hoses. Look for loose, cracked, or broken air hose connections. Check PCV valve...Cheap to replace, could be sticking, then loosen after truck sitting with engine off. A vacuum leak will not give any light indications, and vehicle will seem to run normal when applying gas, but will want to stall or run rough (or want to stall) when at idle or sometimes when taking foot off gas when slowing down.

it may either run poorly all the time, or it will run great for a bit, then run poorly for a bit, and back to running good again. this cycle will repeat until you get it fixed

try pulling the overflow bottle and then the ECM. Unplug the ECM and pull the screws out of the face of ECM add thin washers to screws and the reinstall. reinstall all. the reason is that the screws on 96-98 where slightly long and after time the screws would ground out when hitting bumps or temp rises and gauges sometimes drop to zero and car would stall. Sometimes just stopping at stop signs and lights would cause a stall. If it was to hot it would sometimes take a while before starting

The code means the EGR valve is not opening when the computer commands it.
Causes could be a faulty EGR valve or sensor, a problem with the wiring between the sensor and the computer, or an exhaust leak.

clean the carbs, could also be something in the fueltank, also remove and clean the fuel tap.
When it stops next time turn the fuel tap to PRI, in case the fuel tap need a kit.
also open the tank cap to see if it has vacumn, the vent may be blocked

try adjusting the throttle position switch very hard to adjust right car will hesitate , not idle properly and hesitate when accellerating if not adjusted properly.

Change or clean the EGR valve and install a new catalytic converter.
This should take care of the problem.