Don't get caught out i was chasing a issue nearly the same, changed oxygen sensors, intake gasket, checked for leaks, the pcv valve was a bit stuck but still working, if the pcv valve is not working properly is usually goes to a high idle not lower.

The VCT phasers in the eariler ba's had problems sticking, the corrected this with a cleaning procedure, hard starting and lower and high idle, not only that recently i had a timing chain skip a tooth as someone had done an engine repair, left a cable tie end in the front timing cover area and it chewed an edge off the tooth ! now you ask how does it run ok up from idle, the pcm compensates ! at idle been a tooth out it would either fully retard or advance this vct to change valve timing, so even if you try everything the pcm is at its limit with the cams.

This is just a case i had not saying it is yours ... but dont overlook the basics please !

Some interesting stuff there highkid. Dont think it applies here though.

The engine starts instantly, and idles very smoothly at below 500 rpm so I dont think the phasers are clogged. If it wasn't for the fact that at 450-480rpm in drive at lights the car shakes a bit and the low oil pressure when hot at below 500rpm I wouldn't be worried about it at all. Also I checked with ford FMP software and it said I had the latest update installed. (Actually it said it didnt have any updates for me which I hope means the same thing.)

My gut tells me that a previous owner did stuff to this engine and then when he sold the car he pulled off all the external bits to sell and put the factory tune back on so he could keep the SCT or whatever. I imagine that aftermarket cams with factory tune could cause the low idle issue. I've kind of given up trying to find the problem as I've replaced all the common culprits to no good end. I've just bought Binary Edit fromBPR and will very soon be putting a custom tune on... One that I can adjust myself.. First thing I will be doing is setting the base idle to stay at 750rpm.

just a final update.

The tune that my car had when I got it was a mess.. the VID block (whatever that is) is corrupted and it wouldn't idle in gear without shuddering like crazy.. don't know what they did to it.. but I wasted a lot of time trying to fix an idle problem that couldn't be fixed without replacing the tune.

The new tune has it idling in gear with the air con on at 600 rpmish.. perfectly smooth and nice. Despite getting it nice and hot on the way to work, it had 22PSI oil pressure while idling in gear with the air con on.. so that is good now too.

My cousin has a na ba xt and he had a low idle so the first thing he did as I told him to is to replace the fpr. I did in mine and it fixed my low idle and he replaced his and it idles perfectly now. I would try that but its up to you just my 2cents worth.

Hi Darcy,

What is an fpr? only ford thing I know with those initials is Ford Performance Racing.

fpr = Fuel Pressure Regulator

ah.. mint..

Interestingly, I have a Ba XR6T spare regulator here that Troyman sold me.. currently bolted to an AU fuel rail.

But I doubt I'd be running 12 PSI this morning easily with rich AFR's if I had a faulty regulator would I?