will run fine for most of the time, distributor has been replaced, has a miss every so often found to be a bad plug wire, every now and then it will start running like it is completely out of time, then it will start running good again, happens every once in a while, any ideas what this could be?, have check resistance on coil cold and hot both test good, any help would be greatly appreciated

 

4 cyl efi

is there an engine check light on ?

when was it last serviced

what other work has been done in the engine bay

 

yeah, read a code 12, which I understand to be a knock sensor, distributor was replaced

 

knock sensor is a separate part you can replace

threaded into the engine block under the inlet manifold

http://www.troublecodes.net/toyota/