General xc90 using more fuel but less power

[plasternick]

hi, i have a 54 xc90, had it serviced as usual in jan, and it went like a rocket for a couple of months then i noticed a rise in the fuel consumption, and a loss of power in general, i used to get 29 mpg towing, the same journey in may, and i was down to 26 mpg then i have just done the same journey again in august and it went down to 23, and it doesn't seem to have the same power as it used to have any ideas anyone?, fsh, 108000 miles thanks nick

[skyship007]

Most likely suspects are a blocked EGR valve or a dirty MAF. If you have been using El cheapo supermarket fuel, then it might even be gummed up injectors.
Try cleaning the MAF up with a MAF spray (CRC is a good but cheap company), then run a can of direct feed injection cleaner (Just fill up the fuel filter housing with it when changing filters) like Liqui Moly Diesel Purge.
A good Sunday morning motorway session can also help clean out the exhaust system.

[cheshired5]

+1 for the suggestions by skyship and you may also have a knocking injector. You can hear the knock by using an automotive stethoscope listening to the top of each injector in turn. You can even do the same by listening with a length of hosepipe and the knock you're listening for is very obvious.
If you do try Diesel Purge, skyship's method is the easiest but is also quite wasteful and you won't get the full benefit as around half will be leaked straight back to the fuel tank and diluted with your fuel.
The most effective way is to use the feed and return lines in the engine bay to create a closed system which will recycle the Diesel Purge so it all gets used at full strength. You'll need to pull the fuse for your in tank fuel pump for this method.
It takes a little longer but the job gets done right.