it has been brought up in another thread and didnt wanna highjack it. anyway my knock sensor has melted out in my 4cyl TR. im interested in what exactly it does and whether its worthwhile replacing it. ive talked 2 a few ppl and they said dont worry til the "check engine" light comes on. any info would b great

what do you mean melted out?
the knock sensor on the TR 4cyl is open it doesn't have any plastic or silicon seal over it.
as long as the wire is connected and everything inside it looks ok it should be ok.

it is a piezo-electric plate that will generate a small elec current with vibration, it is tuned to vibrate at the frequency generated by pre-detonation. This current is sensed by the ecu and it retards the timing accordingly.
The current is so small that the wire to the ECU is shielded to prevent electro magnetic radiation (mobile phone, other curcuits, etc) giving a false signal. The ecu is always trying to advance the timing as far as it can within parameters, without getting a signal from the knock sensor.
If the sensor is defective then I would think the ecu would go into a failsafe mode for timing, probably hold base timing, this would reduce the preformance and economy.

can "monjunior" or someone else who works for a mitsu dealer service dept confirm or deny this???

not much to say really after that benau. couldnt have said it too much better myself.
the ecu on these doesnt try to hold the ignition timing on the threshold of detonation, it just runs a set timing map and the knock sensor is there if anything adverse should cause detonation eg poor fuel, carbonising ect. im not 100% if it will throw a code or engine light due to knock sensor, possibly as i remember cc gsr lancer will (roughly same era).
it shouldnt perform properly if it is faulty but it can only pull out a limited amount of timing. it cant pull it back to base timing 5 degrees or anything like that.
i must say i havent seen one melt before...be interestd to have a look. throw up a pic if ya have one supermagna