The airplane had just been purchased the day before the accident and was being flown from California to Texas. The pilot stated that after departure while cruise climbing through 8,400 feet MSL, the engine lost approximately 300 RPM and ran rough. The pilot said he verified that the boost pump was on and the fuel pressure was normal (4.5 to 5.0 psi). Next, the pilot noticed that the EGT was 100 to 150 degrees Fahrenheit higher than normal (1,200 degrees F). The pilot richened the mixture and the EGT continued to rise with no change in power. The pilot stated that the engine abruptly lost almost all power and surged intermittently from idle to fifty percent of its power. At that point, the pilot attempted to locate an emergency landing area. The pilot stated he did not think it was carburetor ice because of the temperatures at the time. He said he felt that it was a fuel blockage or intake leak causing a lean mixture. Wreckage examination revealed no obvious mechanical malfunctions.