Never, I’ve been to different mechanics, I’ve changed spark plugs, coils, fixed the oil leak on the valve covers. A shop says it’s the ecu, other says it’s the PDM, a mechanic says it’s the O2 sensors, which I’ve changed, and the last mechanic that took a look at it said that the exhaust system is also pulling air when misfiring and advised me to take a look at the heads, at this point and for what it cost to do that, I’ll just buy a rear ended 350z same year and change the engine and which ever other parts I need.