I have read that the 4.0L engine can be a little unhappy with platinum plugs on some topic threads on the US forums.
Yet my daughters 4.0L WG had well used copper champion plugs when we purchased it at around 177,000kms, in the subsequent service I swapped in Autolite double platinums and they were faultless for 90,000kms they were only swapped out to troubleshoot another engine problem which turned out to be a worn out cam sensor drive, not the sensor the actual drive unit suffered a bearing failure causing the cam timing to scatter.
Recently I swapped in Bosch Platinum plugs and the car is now going through 300,000kms without and spark plug related issues.
It did sometimes stall in the hot weather a few summers ago only when the A/C was running but cleaning the IAC valve fixed that fault.
Last edited by Classic Boy; 18-08-2017 at 10:42 PM.
|