XSeries-forum

I've had a No. 5 misfire on the truck for a couple of years, but never bothered with it as only came on if you really booted it.
Anyway finally got round to changing the plug and coil pack a few days ago, and as I made a mistake and bought a full set I did the whole lot.
Luckily it got rid of the misfire at full throttle (i forgot just how fast this truck is especially as it might be quicker than standard. Ahem.)
But the big surprise was the massive change in the gearbox operation
I had become used to the harsh gear changes, and the shuddering believing it was just old age and par for the course for a 6 speed box. Apparently not
Probably the best its ever been, I am assuming that the engine torque with dodgy plugs was not what the gearbox was expecting hence the poor shifts. Certainly happy with it.
What im not happy with was the fact that there were 3 types of coil packs fitted and that the plugs appeared to have been tightened with a breaker bar.
And only bmw main dealers have worked o this car.

Torque on the plugs is only supposed to be either 23Nm (12mm) or 30Nm (14mm) depending upon the plug size. Was there any sign of corrosion that might have resulted in tightening up in the bores?

I’d forgotten that model stayed with the 6sp box due to there not being an 8sp that could handle the torque - though the later version could if fitted with the Rolls-Royce ZF 8sp variant as that could handle in excess of 1000Nm.