hi, 1999 st 24. always been slow since buying it last year, got 11000 on clock, it dose not burn oil, runs lovely, gose through a service ok, but put your foot down and it dose pull a bit but nothing like 167 bhp? seems to get worse when warm, and at around 5000 rpm hits flat spot or wall normaly throws like a huge mass of white miss out the exhaust, the car dose not loose any water, never had to top it up, but if you ease of the throttle then boot it it dose respond better.
in 5th gear been up to 125mph no problem, but say at 80 then drop down into 4th with your foot down it hates it and dose not pull, its bad for overtaking! can any one give me a clue what could be wrong, thanks clive.

 

Collapsed cat maybe,they tend to get worse the hooter you make them. Air mass meter possibly.
Best way forward would to run a diagnostic,if it all checks out ok maybe a run on the rollers to see if it is lacking.

 

As said could be a collapsed Cat OR perhaps the IMRC that controls the operation of the secondries is failing i.e. feels breathless and flat usually after 3500 rpm or so.

Search on fordmondeo.org as I'm sure you'll find an accurate diagnosis there.

HTH

Edd

 

Old/blocked air filter.

I know you have just had it serviced BUT somtimes they get over-looked

If not then my next step is a collapsed cat. This would give all the same symotoms you have described

HTH

 

My other half had this problem when she had a new exhaust fitted. It turned out to be the sensor on the exhaust Manifold was left disconnected. Can't remember what the sensor is called. But we reconnected it and all was well again.

 

lambda sensor

 

Thats the one. Couldn't remember the name of it for the life of me.