[quote name='petejenkin' date='Aug 12 2004, 04:00 PM']Your right, its only a small resistor that you put between the connections of the O2 sensor. Loads of damage can be done. Its an old trick that would work a bit on older mechanical injection cars - like the Capri with Bosch K-Jetronic, but defo not a nice car like ours.
for anyone who might be tempted to try one - LEAVE IT ALONE - IT WILL DAMAGE YOUR CAR AND COST YOU 000'S TO REPAIR - maybe

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It's actually put on the air intake temperature sensor to make the ECU think it is very cold and therefore nice dense air so it puts in more fuel. The problem though is that Toyota tend to run a bit rich anyway under load and then when it goes 'closed-loop' it uses the O2 sensor for it's mixture settings.