Timing issues? Do I need a pro?

[Sambo72]

Gday - I have a 2004 BA falcon - 120,000 on the clock. Runs well but I'm think the timing might be out or maybe it just needs a EFI cleaner. I'm used the old school fords which is why I ask (timing light, adjust distributor). The engine feels as though its timing is out - its running between 500 to 700 on idle while in drive (auto obviously) and cant make up its mind between the 2 - its making the car rock side to side which used to be awesome in my old v8's but is really annoying as its not steady if you know what i mean. Its been getting progressively worse. I did a home service about a year ago - just sparkies, air filter, oil etc but no pros. ie no computer hookup. So do I need that or just EFI cleaner and if so would you recommend the spray into the air filter or the petrol tank one.

Cheers

Sam