www.jec.org.uk

hi, I have a probem with my 1986 twr 3.6.
I have replaced the ecu,fuel filter,crank sensor and temp. sensor. The engire starts instantly and runs well above 2k revs, or at any revs, once warm.
However when starting from cold the engine is very lumpy at first, and ticks over at about 1k revs. Once warm the tickover goes down to about 400 revs. The engine temp. indicator on the dash never goes higher than a reading of about one third of the middle ( ie. well below normal)
any advice would be welcomed.
thanks jim

Don't know enough about pre-facelifts to comment in detail, but first thing is to verify the temp gauge.

Is the car genuinely running cold? If so, a change of thermostat would be a good start. If it is getting to temp and the gauge is lazy, short the wire on the temp sender directly to earth (making sure you do have the gauge sender) and note if the gauge goes to fsd. If it does, then chances are the sensor is faulty - quite common and a replacement shouldn't break the bank.

Once you know the answer on this, the idle speed may be fixable.

Has the gauge ever read normal? They really are not in any way reliable! Sometimes cleaning the back of the instrument pack and the plugs gives a better reading, which might be worth a try.
The lumpy idle and low tickover when hot sounds like it is running rich at low revs.
As the engine wears it doesn't pull as much manifold vacuum and the ecu can't compensate. There are two fixes.
1) overhaul engine':shock:'
2) AJ6 engineering make a modified ecu with a trim pot to compensate, this worked a treat for me':D'
This is just what happened with my old 3.6, but I hope it helps.

Having said that have you cleaned the throttle butterfly, that could do the same thing.