Does it make a difference if the leads are resistive or not.i measured the ford ones and they are 10k ohms,i have another set of leads which cost me 80 quid,big thick leads,and there is no resistance

 

Resistive leads are pretty essential where ecu's are used, as are resistor plugs, wires leading to the ecu can pick up interference, esp the tps, as this is closest to the HT leads.
You can buy shielded overbraid, that you can run any wires through if there is a interference problem, and then earth one end of the braid.
With interference it confuses the ecu and causes all sorts of problems to misfires cutting out etc.
tabetha

 

will stick with my new ford ones then.
thanks matt