Hi i've just bought a 59 reg is220d with 123k miles.
When I bought it, it was listed as having an egr issue and it went into limp mode around 5-6 times on the 130 mile drive home requiring me to pull over and restart the car every time. During this journey the car averaged 39mpg according to the computer. and occasionally had white smoke out of the exhaust, as well as a strong diesel smell out of the exhaust.
The first thing I have done since then was cleaning out the egr valve with 2 cans of carb cleaner and this seems to have resolved any warning lights, white smoke, diesel smell and complete loss of power. However during my 70 mile trip commutes over the last 2 days i was only able to average 31mpg. This is after averaging 30mpg around town on the weekend.
I was expecting for the mpg to improve and not decrease based on what I had read.
I have also ordered some maf sensor cleaner which should be coming later this week, and taking off the manifold to clean it out is unfortunately something I wouldn't be able to do, despite the well written guide on it I have found here on the forum. If this is likely the issue then I would have to get a mechanic to do it.
Does anyone have any suggestions on what the issue could be, or what I should look to do next to try and resolve the poor mpg? When I filled up the tank I did use esso supreme and added some DPF cleaner as well.