Here's the story: My G is a 2005 with the rev-up engine and 175,000 on the clock. Suddenly I got a high idle and code P1078, Bank 1 exhaust timing sensor. After replacing the sensor with a Hitachi sensor, the idle is still high and the code comes back immediately. One mobile tech stated that it "needed to be on a Labscope" while another stated "A friend of mine had a G35 like yours and it needed a timing belt." Now, I thought that was hogwash as the rpms were not jumping around, the power is good, there is no rattling in the engine; all of which to me would suggest a bad timing chain. Bank 1 (green connector) camshaft sensor changed in 2023 when slip light came on and crankshaft sensor replaced in 2022. My plan is to replace both sensors on Bank 2 even though 1084 is not a code that was ever shown. Just wondering if anyone solved their high idle problem by replacing all of the sensors, even those not indicated by a code? My plan is to go Bank 2 both sensors new and a new crankshaft sensor unless that is simply a waste of time.

The second mechanic said "those codes will keep coming back if the timing chains are going bad", even though it has been the single P1078 code. I think maybe someone on this forum understands our vehicles better than him.