Mondeo st220 issue

[PERNERA2009]

Hi. Can anyone help. I have a 2002 st220 that is running abit rough, when you decelerate you can hear like a flappy noise( sorry poor description) it's like the air intake opening and closing repeatedly. I thought I would change the maff sensor, but now it's even worse, runs like a dog, and I even stalled twice on way home. I'm confused and gutted

[Zad]

Could it be misfiring? Pops and bangs in the exhaust. It is possible the original spark plugs haven't been changed, they have a long service interval and are a pig to get to.

[PERNERA2009]

No pops and bangs, brand new plugs 3 months ago

[Glasgowrob]

did you fit the plugs yourself? or at least watch them being fitted.

utter pig of a job and most mechanics ignore the rear bank

[road_rager]

Hopefully you didn't get an eBay Maf sensor? If you did bin it they are useless. Other things to look at would be 02 sensor/s

[stevefesta]

Have you checked for air leaks?
I had similar and there is a hose that runs from the rear bank that over time will split.
It is the breather hose, near the end if this thread is a good description of where it is:

http://www.stdrivers.co.uk/forum/topic/32277-advis...

Edited by stevefesta on Thursday 19th April 22:42

[PERNERA2009]

I try and answer the suggestions. Yes I saw the plugs being changed, they were originals and completely gone. I've had breather hoses changed. The maff is an original from Manchester auto electric. Like I was saying the car ran abit rough before maff sensor fitted, now worse, you can also hear that sort of flappy noise once you have come to a stop and engine calming down

[Squishey]

As mentioned check the breather at the back of the inlet manifold for splits. Check that all of the HT leads have a good connection at both the plug and coil ends. Check that the inlet manifold has been bolted down evenly and to the correct torque setting after the recent plug change.

Take a video of the car making the "flappy" noise that'll make things a lot easier for us.