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

[FERG_51]

Very hard to diagnose from here, but could be a vacuum leak in the intake manifold, with the engine running spray some aero start along the intake manifold where it meets the head. See if the revs pick up and that might be your problem. Only an educated guess but worth a try.

[aussiblue]

Very hard to diagnose from here, but could be a vacuum leak in the intake manifold, with the engine running spray some aero start along the intake manifold where it meets the head. See if the revs pick up and that might be your problem. Only an educated guess but worth a try.

Yes; it very likely a inlet manifold gasket leak but note spraying Aerostart and water etc often wont work that well in detecting vacuum leaks on these computer controlled fuel injected engines like it it does with old style carburetor based engines.

As I have said numerous times on this forum (e.g. https://fordforums.com.au/showthread...ght=smoke+test) :

Use a length of windscreen washer sized hose with one end in or close to the ear to listen for the no mistaking tell-tale sucking noise of a vacuum leak while poking around under the manifold at idle (with engine both cold and hot as the gap between the head and the manifold changes as the metal in the manifold and head expands and shrinks with heat and cooling).

Note that the old pre-computerised fuel injection trick of using/spraying engine start sprays, benzene , water, oil etc around the manifold will most often not work to find these leaks as the ECU rapidly adjust for the change in air in the mixture and it's hard to pick up any change in the engine noise or rpms using this old method. As it the lowest point of the gasket that burns out creating the vacuum leak, you are also fighting gravity with any gases or fluid sprayed around just falling to the ground rather than being sucked in where the small piece of gasket has burnt through.

The manifolds typically leak at number 1 and or 6 as the nuts on the manifold retaining studs there loosen over time and the very bottom parts of the gasket then burns out. Because only a small part of the gasket has burnt out, simply re-tightening the nuts won't fix it and you will need to replace the gasket remembering to torque to specification in a circular pattern from the center of the manifold outward.

A smoke test will also work but the hose/tube listening trick is much simpler and easier