250 Se-l Auto Sputtering And Low Economy.

RNUK · October 14, 2015

Hi, my 2005 is250 SE-L auto economy started to drop through the floor (from 27ish a couple of months ago to 22.5-23) and today it sputtered on idle and stalled. It started straight away but when I came up to a junction on a hill this evening, it again sputtered and 'kangeroo'd' a little.

It was serviced in June (before I purchased it) but I have recently had an air filter replacement warning come up. I've checked it and it seems to be ok. I have only put 3k on the clock since I've had it.

Any ideas what could be the issue?

Verbout · October 14, 2015

I would start with the easy fix first.

Check all brakes are not binding/calipers seized.

Then check for any OBD codes.

normski2 · October 14, 2015

If you know what is and what to do.....I'd take a look at the mass air flow meter.

If you are not sure...Google it and you'll find many YouTube vids on how to clean it with care. It could well be a bit dirty given that you have a 05 vehicle.

is200 Newbie · October 14, 2015

Air filter replacement warning? Isn't this user based (info can be added to the maintenance schedule by the user on the head unit in that warnings/notifications appear after a set time when things become due such as oil change / brakes / air filter?). The fact that the warning has come up may be a bit misleading. Has it come up on the head unit or on the instrument cluster?

I would side with Normski on this - and I would also check your fuel cap is on tight.

The service you have had done may have dislodged some dirt when changing the air filter (if it was changed)

RNUK · October 14, 2015

The engine check completes without error on startup but I get the maintenance warning on the head unit. I checked the filter and it seemed OK so just reset the warning, it was fine for a while but came back on again. I've reset it again, but I guess the MEF would cause a sensor to think the air filter is dirty and needed replacement, no?

I'll check the MEF and clean as per instructions on here and see if it helps.

I need to take it in to check the calipers at some point because I get a "clonk" under braking sometimes so I guess they are possibly beginning to seize.

Verbout · October 30, 2015

Any resolution to your issue?

RNUK · October 30, 2015

Early days yet, but yes I think so. I checked the brakes immediately and all appears fine. I've only just found time to clean the MAF and early signs are pretty good. Wife's car failed the MOT so had my hands full sorting that plus it's dark when I get home from work now.

I cleaned with Isopropyl spray from Maplin and let drip-dry. re-installed and the economy immediately went back up to 26-27, the engine is a lot smoother and power delivery is quicker. It's early days yet but once it's been going week or so I should have a better idea. Certainly on the face of it, no more 290 miles between fill ups and no more accelerator lag or spluttering.

Interestingly, started immediately after a tank of Shell V-Power, which isn't normally what I put in.

Thanks all for your help.