Does your Freelander 1 TD4 appear to be over or under fuelling? Does it not seem to have the power, fuel economy or smoothness that it used to?

You may have a problem with your MAF sensor (the original sensors are Bosch sensors).
To test this, unplug the MAF and see if things improve. If they do then the MAF sensor is your problem. (The MAF sensor is located at the rear of the engine, near the oil filler cap and air filter, you will need to remove the air filter to access it).

Once you have identified the MAF as your problem you have three options:
1. Clean the MAF sensor – they are a bit delicate so this is not a great option;
2. Replace the MAF sensor with another Bosch MAF sensor.
3. Replace with a Pierburg MAF and Synergy-Ronbox to give more power or fuel economy (depending on the settings). We have found everybody who has opted for this solution to be thrilled with the results, and it is not much more expensive than a replacement Bosch MAF.