Hey guys, i was wondering if anybody could diagnose the problems i am having with the BA XR6 auto i have recently bought second hand.

Firstly the car is on injected gas, but im pretty sure it shouldnt matter - explanation later. First of all as of late, occasionally when i put the car from drive to reverse or park, or when i turn the wheel at low rpms the RPMs dip significantly, occasionally to the point where the car stalls completely. In the service history of the car, on the ford service notes it states 'investigated low idle' so i believe its unrelated to the fact its on gas.

Secondly, ive noticed only recently that if i give the car a bit of a kick, either in 'performance mode' or in just in drive, if im in first gear the rpms climb to about 5.5k, then the car stops accelerating, the rpms stay at 5.5k and nothing happens. If i let off the accelerator the rpms dip, and then the car suddenly changes to second. Previously the car changes at 6.whatever thousand rpms and continues to accelerate, however recently this has been occuring.

I was wondering how i should best go about fixing these issues, and if they are related.
any advice would be appreciated, cheers.

G'day Mate,

Try turning on the air conditioner and see if the it ramps up the idle a bit to compensate for engine load. You should notice the idle drop a bit first then go back to where it was idling before. Then turn the A/C off, the rev's should go up a bit then back to its normal spot. If this is happening it shows that the pcm is controlling the idle speed.

Then try hitting the steering wheel. The engine revs should raise a bit to compensate for the load, then over shoot a little when the load is taken off. If it works for the a/c but not for the steering, there is a pressure switch on the steering rack that is probably no good.

The other thing worth trying is to reset the pcm by disconnecting the battery and going through the re-learn procedure.

Oh and another quick check, check inside the throttle body to make sure it has not gunked up around the butterfly, restricting the air flow at idle.

The gear change issue could be related to the throttle position sensor and the Tmap sensor. Also on the factory gas systems for the BA there is a plastic pipe that runs from the air box to the gas converter, if this is present on yours make sure there are no holes in it as that can cause performance issues. Does your gas system use a stepper motor on the gas outlet? It will have 4 wires going to it.
Check the idle problem first.

Cheers Mick

Last edited by Mechanic Mick on Thu May 16, 2013 8:56 pm, edited 1 time in total.

Could be the power steering pressure switch, which is supposed to tell the computer to increase rpm when the steering is turned to stop it idling too low and stalling. It's at the top of the power steering high pressure line, close to the pump. You could tell if it's faulty by unplugging it, if acts the same, it could be your problem.

Not sure about your second problem though.

Just thought id advise what the problem was. Turns out the previous owner had installed cheap spark plugs and coils, which according to a different mechanic to my normal one were known to be un cooperative with the falcon. 6 coils and 6 plugs later, everything seems to be running fine on the stalling / low rpm side of things.

The only thing now is the gear thing, i spoke of previously. Hopefully ill get that fixed up next service (: