Hi i have a 2004 TL AWD. Running well, no issues, new alternator 12 months ago (and less than 8k km since then and new battery 2 years ago). Started to have an intermittent problem. Occasionally the engine will crank but not fire for 3-4 seconds. if i turn the key off and crank again it fires. Seems to only happen when cold, starting again warm seems to be ok. Doesnt happen all the time, one or two days it does it, then nothing for a couple of weeks.

Reading around people have suggested a fuel issue such as a fuel pump or fuel pressure regulator, or dirty injectors/ plugs , or some suggest a battery issue. Dont have any battery lights and all systems appear to be working ok. Don't want to spend a fortune at a garage, so any ideas...hope to trade in a couple of months so wont be going far till then.

My TL AWD does a similar thing when the battery gets low. Usually happens after a couple of months of driving short distances ie: 3 km's in the morning & 3km in the afternoon (no long runs to properly charge the battery). The car will crank for 3-4 seconds start then stop for no apparent reason. Car will then start & run OK. Once it starts to do this I charge the battery till the charger auto turns off. The problem then goes away for another 3-4 months - or more if the vehicle does longer runs.

Cheers

What kind of battery do you have? A lot of those imported batteries don't last as well as the locally made Century or Exide's. I'm saying this out of experience, in terms of what my friends and colleagues have experienced.

Its a century, perhaps 2.5 years old but only done ~20k km i reckon. Water level was down a bit, so topped up over the plates and see if it improves.

What Century Battery? I personally would only get a 'Hi-Performance' or 'Ultra H-performance' range one. That said, fluid levels can get low, even in 'maintenance free' batteries! Maintenance free just mean it's most likely a calcium lead-acid battery, which the 'Hi-Peroformance' and 'Ultra Hi-Performance' batteries from Century are.

You should only have used demineralised/destilled water as tap and even ran water contain contaminants. Inox Battery Conditioner (you can get it from most auto places) works great, I would recommend purchasing that to fill up the cells.
At Supercheap: http://www.supercheapauto.com.au/online-store/products/Inox-Battery-Conditioner-92mL.aspx?pid=9642#Cross

Website:
http://www.inox-mx3.com/inox.htm