I haven't got an ETEC but a DI. My tell tale goes from being warm to cold to warm to cold etc if I leave my hand in position for a length of time at idle.
It might suggest a stat is stuck in the open position, but this is unusual as they normally stick shut and overheat the block. Are you sure you've even got a stat in line, might have been taken out previously and not refitted.
Incidentally my 150 has 3 stats, one for each block and one common to both sides.
Hope that helps you a bit.
Looks Slow but is Fast
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