Been having crankshaft sensor error codes for awhile. Eventually led to rough/long start and then crank with no start. Shop replaced the timing chain guides. Timing chain is in good condition and aligned. Shop suggested that at my mileage (225,000) other major engine components could become an issue and that it would be more economical in the long run to replace the motor. While I buy that logicI can not come up with the thousands of dollars quoted for a replacement. Wondering if it is worth investing in new camshaftsrockersand liftersas that would be more reasonable budget wise.