Do you remember the exact diagnostic fault code number?
The common mistake is fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. First wiring and connector problems must be explored, then you must consider related mechanical problems, such as a loose timing chain or worn tensioner.
When the fault code doesn't set again right away, it is often helpful to have a scanner with record capability with you while driving. When the problem occurs, you press the "record" button to take a snapshot of a few seconds of sensor data. Due to that information passing through the scanner's memory, the recording actually starts a few seconds before you pressed the button. Later, that data can be reviewed slowly to see what took place.
Tuesday, October 13th, 2015 AT 6:50 PM