Try This......

[gaz666]

350i, Lovely starter,perfect idle,smooth acceleration in all gears,nice engine temp.Then slowly the temp started to play up all over the place. A few days later followed by bad starting when hot.Then pinking in all gears and occasional erratic idle and slight power drop. Checked the usual, timing, thermostat, airlocks, if u have any of these problems try changing the coolant temp sender on the engine block just behind the alternator below the thermostat housing. I did! All is perfect now and all for £6.50..Turns out it sends the wrong signal to the ECU when knackered and easily overlooked.