Help! I have a Focus 1.6 TDCi estate and it has done 108k miles. The car has had a number of issues resolved over the past 3-4 years of my ownership (68k when I bought the car). But the car has a lack of top end power. In the last 15 months/12,000 miles, I have had the following items done (in relation to the engine! - and I have spent more than the motor is worth!!!)

- New DPF & fluid at 96k

- New glow plugs at 96k

- New recon'd turbo at 104k

- New EGR valve at 104k

- Cleaner added via fuel system at 104k

Now, the current problem.....

After the DPF was changed, things seemed 'better' for a while. But the power at the top end of the rev range has fallen away. The basic situation is that when driving the car along, once you get to c3,000 rpm, the car no longer accelerates. It kicks out quite a bit of black smoke, but it has been worse! When the engine is cold, the loss of power doesn't seem so bad, but quickly drops as the engine warms up. It is often better to accelerate by only slightly depressing the throttle, rather than 'flooring it'.

I have read a number of posts via Google search and one that I do wonder about, is whether there could be an issue with air leaks in the intercooler pipes. But, I do not know if this would cause the loss of power as described. Or is there something else?

I am not somebody who understands engines!

Thanks in anticipation,

John

I would be tempted to be looking at the MAF sensor, these can degrade over time and cause all sorts of running issues. Ideally though you need it on some decent diagnostics like Ford IDS or Forscan to see if any error codes are present.

A common trick on the BMW M47 lump in my ZTT was to unplug the MAF and see if performance improved as these MAF's do go out of spec even at very low mileages, the ECU will run at default parameters and usually would indicate if it was a MAF issue.

You can check for intercooler hose boost leaks as well as this would affect performance but I would expect this would be throughout the full rev range.

Thanks Simon. Sounds like the MAF is the first thing to look at. Out with the Haynes manual then!!!