Was told "Camshaft codes timing has jumped"

Hi, I bought a used toyota celica GT-S(2003) 6-speed manual recently with high mileage(195K) on it. It had a noise from the engine from some belt I guess. Before going to the mechanic the same week, the car started chocking and the check engine light was on. The will be running but it will choke on and off like the fuel is not burnt. I went to a mechanic, they replaced the timing belt and cleared the error code. It was find was three days without any sound but after that, car started chocking again. This time, the mechanic cant find the fault code. He redirected me to toyota service center where they gave me a shock like I have to change the engine. The problem they mentioned was "S10 camshaft codes timing has jumped, recommend fixing with used engine". Is there any work around which can fix this problem? Any help will be greatly appreciated. I havent even drove this car even for 100 miles.