Don't split hairs mate:), check everything that can affect your fuel economy such as tyre pressures, clean air and fuel filters, cats and a serviced gearbox and diff. Check your wheel bearings also. If you believe that the air charge temp sensor is the source of your woes, do a ECU diagnostic check and see if it is in fact the problem.

Mate, what does that mean? Split hairs?
Like I said in my ealry posts, this was the last step, I've done everthing else you just mentioned.

Trip computers are not the be all and end all. They calculate fuel consumption on average km and fuel left in the tank. Don't put too much faith in trip computers.

By splitting hairs I'm suggesting that you placing too much focus on that sensor in the overall picture of fuel economy in your V8. If you are really doubtful regarding its condition, take out the guess work and do a diagnostic self test and it will tell you if you have a problem with it or not. If you need a hand with the diagnostic side, just ask

I agree.

If i get another 100km out of a tank which it looks like I will, then these sensors I changed, I do beleive were at least small culprets in the overall problem.

Not saying they were the exact cause because, like you, I beleive they weren't directly responsible.

I'm just saying they did need to be changed, no different to every other filter/sensor that needs changing during the life of the car.

So how do you perform a diagnostic check? (In simple terms please, please remeber I have no electrical knowledge whatsoever, I dont have multimeters, don't know how to use them, if I need them to perfrom this operation, then I'm happy to buy a set and learn).

Thank you.

I would like to learn also as no electrical shop even has the equiptment for a EB-ED (they say there tooo old).

I know the EF-EL throws codes on the dash so there easier to find, as im trying to find out why my break fail like keeps coming on. They say it keeps the codes for 50 starts but how would u do a self diagnostics test on these cars?

OK this applies to all E series V8s.

Before you start, you will need:

1) A jumper wire with small alligator clips and;
2) An analogue multimeter, that is, with a needle.

In EB-ED Falcons, there is a white plug that sits below the fuse box. On EF-ELs this plug hides inside the fuse panel in the lower right of the dash. It is a female plug with very small flat terminals inside. To test the ECU for stored fault codes, you need to connect both the upper far left pin, with the lower far left pin. These are ENG STI and ENG GRD. After you have joined them together earth out your black wire on your multimeter and connect the red wire of your multimeter to the 5th pin from the left(count the pins starting at the top left and stick your red wire on the pin #5). Turn your multimeter on and select 20V DC, put your keys into your ignition switch and switch the key to ON but do not start. Your ECU will start clicking and you see the needle moving about.

How to decipher what that needle is saying?

On EECIV(EB-ED) it will spit out 2 digit codes but on EF and EL EECV it will use 3 digit codes.

An example of a buggered ACT sensor on an EL V8 is 112 and/or 113. Your needle will go for code 112:

----1---pause----1---pause------1-------1

another example is 117, a dead coolant temp sensor on an EL V8:

-----1--pause--1--pause-1----1---1---1---1----1---1

It will cycle through all the error codes before stopping. In between each code, the ECU will pause.

It is very handy to have a notepad and pen nearby to right down each code as they come. Try it out, you will not blow anything up if you do exactly what is spelt out here.

How would u know what code is what?

Where would find the codes, who has a list?

Max Ellery's workshop manuals. Post up the codes in a new thread and someone here will tell what it's for. I've got them all at home.