I am having some trouble figuring out this problem with My XJ6. I turn the key to start the car and the starter just clicks like the battery needs to be charged to is a week battery. I turn the key a second time and the car starts right up. it does this about every other time or so.

1) Battery is good (tested twice by professionals)
2) Starter has been replaced (Autozone Starter)

Has anyone had issues like this? or do you know some possible causes?

thanks

Autozone remans have on multiple occaisions caused me to pull my hair out. I have had to replace them again and again. As a function of my experience with Autozone my knee jerk reaction would be the new starter is bogus. A secondary possibility might be a weak or bad connect at the battery, a loose or dirty connect at the ground cable to chassis port or a bad connect at the starter. Since you say it clicks when you roll the key to the start position I'm guessing the solenoid is getting the signal to close the circuit that energizes the starter. Sounds like inadequate voltage to the starter motor or a bad starter.

My thoughts are, in no particular order:

Starter replaced, still the same??, not the starter me thinks.

Electrical section of the ignition switch is cruddy, as most of us remember from the earlier cars, switch is basically the same.

The battery +ve terminal fused link is making very poor contact, had that one.

As said, the earth straps at the battery and engine are poor, not too high on my list, but definately a maintenence item in my opinion.

The starter relay is just tired.

The various +ve battery cable connections under the bonnet (hood/whatever) are not clean/tight.

Thanks Guys, I will check all ground connections and battery contacts and make sure their all clean and good. Ill check the relays. I was thinking the Ignition switch was not giving the starter enough power. its so weird that it starts every other time or so. Ill get back to here as soon as i check all power connections
.

Have a read of the thread a few above here, "Weird problems", about the water getting into the ECM tucked inside the RH "A" pillar trim, where the gas pedal would be on a RHD car??.

Maybe this is the clue on so many of the no start/weird behaviour of a lot of the X300 threads, dunno.