Car suddenly running lumpy! After an afternoon's troubleshooting, I've determined that I've got a stuck injector. Applying 4v to the other injector units produces an audible 'click' but does nothing for the dead one. Resistance is the normal at ~2 ohms, so it's not an open coil. I'm assuming (?) that a bit of dirt has worked its way into the mechanism, and that the piston / valve mechanism is jammed. Are the injector units remotely user serviceable? If buying an injector, or set, from a junkyard, is there anything specific to look for? Thanks