Morning all,

I have a 2005 TDCI 130 with 80k on the clock. Recently the car has started running slightly rough between 1500 and 2000rpm. It is only detectable on a steady throttle and appears worse in 4^th, 5^th, and 6^th although this could be because I am generally accelerating when in 1^st, 2^nd and 3^rd and therefore not driving at a constant speed in the lower gears. It feels like a slight misfire. The car pulls strongly and cleanly when accelerating – the problem only appears to be on a steady throttle. Fuel economy is fine at around 50MPG.

Car was serviced around 3000 miles ago and the problem only started in the last few hundred miles.

Any thoughts on what could be wrong?

Glowplugs, injectors, DMF, something else?

Thanks in advance.

i would start by removing and cleaning the egr valve its a simple job to remove but messy cleaning it out, also check the intercooler pipe for splits, its the large pipe from the bottom of the egr valve.

when was the last time it had a service

The car was serviced about 4000 miles ago.

I've removed the EGR and cleaned it. Also checked the intercooler pipe for splits and eveything looks ok.

I've getting plenty boost pressure andthe car pulls really well.

I'm beginning to suspect either DMF failure or injectors.

I'm assuming either will be expensive to fix :-(

I'm beginning to suspect either DMF failure or injectors.

I'm assuming either will be expensive to fix :-(

Try injector cleaner/fuel system cleaner. It might work and it is relatively cheap and easy. Also check for air leaks around the air filter to inlet, particularly if it feels like it needs more throttle than it should do to pull away from 1500 - 2000 rpm and then pulls ok.

If those don't work, you probably are on to something more expensive...

The problem is almost certainly the EGR valve, Easiest, cheapest and best way to sort this is to fit a blanking plate, (solid, with no holes to let the gasses through, stainless steel preferably 3+mm) if you have a euro3 engine you can fit it with no problem, a blanking plate fitted to a euro4 often makes the EML (engine management light) come on (sooner or later) this can be annoying for some people and can "mask" other faults that would otherwise put the EML on, many euro4 mk3 Mondeo owners prefer this to the alternative (the non-blanked/ disabled EGR system contaminating the inlet manifold with carbon/ gunk, and squirting burnt carbon monoxide into the inlet replacing clean air)

Blanking the EGR is standard practice on Mk3 diesels, for best, reliability, performance and economy (and good running) some have removed the system entirely

the plate costs about a fiver online

A diesel only has its particulates measured for the mot, so it will not fail because of the plate (though the EML coming on may be a failure - but this can be reset with a code reader)

let me know how you get on with it

PS - best to clean out the carbon/ gunge the EGR system has deposited from your inlet manifold