To those of you with mk3 ST petrols

[All that jazz]

How long does it take for your oil temp gauge to move (the left most of the 3 on top of the dash)? Mine takes forever and manages to get to about the 1/4 way point after I've arrived at work, 12 miles and 25 mins away. That seems like a long time to me.

[All that jazz]

Ron240 said:

It does take quite a while for the gauge to move, so nothing to be concerned about.
My journey to work is 8 miles with most of it being dual carriageway, and by the time I get there the gauge has only just started to move.

Slightly reassuring then! I thought my thermostat(s) were on their way out. For reasons unknown my mpg has taken a nosedive down to 25 and the car feels like it's holding back, especially on the overrun where instead of it rolling along quite nicely it now feels more like a diesel with an engine braking feeling. It's not bad but it's noticeable; the kind of feeling you get if your tyres are low on pressure or you're driving into a stiff headwind. It's in for service on Friday as it's 12 months since last oil and filters change. Heopfully that will fix.

[All that jazz]

Cheers Neil, useful to know. It's in this Friday for oil, filter, air filter, plugs and new front pads so I'm crossing my fingers that it comes away 'fixed' although I have my doubts. It really does slow itself down when coming off the gas and my mpg has taken a real nosedive, currently sat at 24.8 which tells me there is an underlying issue as it's never been under 26.7 til now.

How did you discover that it was the air inlet sensor? Did you have EML on because main dealers usually send you away with "we can't replicate the fault" if there's no EML on. FTR my EML is not on.

[All that jazz]

neiljohnson said:

My fuel consumption was also poor but I had an intermittent flat spot when accelerating tbh I didn't expect them to find anything as the fault was impossible to replicate but I mentioned it to the dealer when they replaced a faulty passenger mirror & when I picked it up they explained they had found the fault

There was no engine management light on but it was like a different car on the way home

No mention that the car was mapped either

Nice. I read on a ford forum that you can tell if it's the intake air temp sensor by disconnecting it and driving it around for a bit. If it drives fine with it disconnected then (obviously) that's what it is so I'll definitely try that if the service and plugs don't fix the issue on Friday.

[All that jazz]

Just got it back from service and it's still the same, maybe worse . Mpg now down at 22 and idle rough as fk. Feels about 50hp down on power and have to mash the pedal to the floor to get it to shift whereas before pedal was really light and it went like a rocket.

[All that jazz]

neiljohnson said:

All that jazz said:

Cheers Neil, useful to know. It's in this Friday for oil, filter, air filter, plugs and new front pads so I'm crossing my fingers that it comes away 'fixed' although I have my doubts. It really does slow itself down when coming off the gas and my mpg has taken a real nosedive, currently sat at 24.8 which tells me there is an underlying issue as it's never been under 26.7 til now.

How did you discover that it was the air inlet sensor? Did you have EML on because main dealers usually send you away with "we can't replicate the fault" if there's no EML on. FTR my EML is not on.

My fuel consumption was also poor but I had an intermittent flat spot when accelerating tbh I didn't expect them to find anything as the fault was impossible to replicate but I mentioned it to the dealer when they replaced a faulty passenger mirror & when I picked it up they explained they had found the fault

There was no engine management light on but it was like a different car on the way home

No mention that the car was mapped either

Which is the inlet air temp sensor on the mk3 Focus ST? There doesn't seem to be one. The only sensor on the inlet piping is the MAF. Is it that you mean? I have disconnected mine now and initially it felt a little bit more perky but I think it was just placebo effect as it's still rather laggy and hesitant. My mechanic now thinks it could be the boost control solenoid as I'm having some rather sporadic readings on the boost dial when WOT (this was before MAF was d/c). My mpg is now down at 21mpg .