SR22
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 50; Flight Crew Total 650; Flight Crew Type 500
Physiological - Other
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Illness / Injury
Flight Crew Diverted; Flight Crew Landed As Precaution; General Declared Emergency
Aircraft
Enroute; after initial climb to 13;000 feet and setting cruise power; I began to feel disoriented; confused; nauseated and groggy.  I was wearing O2 and checked my O2 saturation and found it to be 97%; however my pulse was 130.  I was concerned but not alarmed.  However; I found that my fingertips and end of my nose began to tingle and feel numb and I became alarmed.  Since my O2 saturation was good; I suspected CO effects from an exhaust leak and was concerned with my ability to continue the flight.  Since I was feeling ill; I decided that the best decision was to land immediately.  I was near and airport notified ATC that I was declaring an emergency and began an emergency descent to [a nearby airport].  I landed uneventfully 5 minutes later.  Since I suspected CO (carbon monoxide) poisoning; I left the plane [there] and hired an A&P to inspect the plane for exhaust leaks before returning to retrieve the plane.  I continued my trip via commercial airline.Although I do not have proof; I strongly suspect an exhaust leak and CO poisoning as the plane had backfired in the day previous; which was unusual.  Knowing that a backfire could indicate an exhaust leak; I should have removed the cowling and closely inspected the plane before flying again.  The long climb; flown rich of peak mixture probably contributed to CO entering the cabin.  Additionally; I have purchased a CO detector for use in the plane.
SR22 pilot reported feeling the effects of suspected carbon monoxide poisoning; an emergency was declared; and a divert accomplished.