Ford Falcon Engine Problems

It sounds like a connection problem, or it could be something like the crank angle sensor. It needs to be checked by an auto electrician.

A rotten egg smell is usually associated with a catalytic converter that has failed, but it's unusual that it has happened as such low kilometres. It will not get any better with age, and the usual way of fixing it is to replace the converter.

No, but I would stick with what you've been doing. You've had a great run, why change now.

Before you jump to any conclusions I would do an old-fashioned fuel economy check by actually measuring the fuel used over a distance, which would give you a pretty good guide to what your car is really doing. Ford claimed a combined average of 10.1 L/100 km. Now, I wouldn't assume that your car would get the same, as the Ford figure is established in a laboratory and yours would be a real-life number, and they could easily be different. But you should get a figure that is reasonably close to Ford's. If you get more than 14 L/100 km on your test I would suspect something is wrong. When doing your test take the car on a reasonably long run, your short stop-start driving cycle might be the reason for your apparent poor economy.

Sit down with your dealer and go through all the issues with him and seek a resolution with a time frame attached so you know what will be done and when it will be done. If you don't get any satisfaction with the dealer, elevate it to Ford directly. After that seek legal advice. Ford has a responsibility to fix your car, and while the service you have received appears to have been appalling it does appear that there has been an attempt to repair your car. I doubt that you would have much success in getting a replacement car while there are moves to fix yours. Despite the run-around you have received from dealers, the problem cannot be difficult to fix, any competent mechanic should be able to do the job. Stick with it and be demanding.

It sounds as if the fan is coming on when it shouldn't, so have the dealer check the temperature when it does kick in, or simply have the fan replaced.

By the latest system I assume you mean liquid injection. You couldn't update your current system to liquid injection, you would have to remove the old system and have a new system installed. But my recommendation would be don't do it, the advantage of liquid injection over vapour is not clear. What you've got is arguably as good as you can get right now.

You obviously believe that the mechanic who replaced the chain guide set the timing incorrectly, but two years after the work was done makes it really hard to blame him. If the valves were hitting the pistons as you believe they were I would have expected it to show up long before this. If you want to pursue it get a creditable engine guy to inspect it and give you his opinion.

I doubt that it was ever 11 L/100 km on LPG. I would accept that it could be 11 L/100 km on petrol, and if so I would expect the consumption to rise to about 14 L/100 km when converted to LPG. If it returning 20 L/100 km on LPG then I would take it back and have the calibration of the system checked, I think that's where your problem could be.
 

No, it is not normal, there is something amiss with it and I would urge you to have it checked. It could be related to the cold enrichment used on the engine to make the engine run smoothly during the cold running phase.