samer

Hi
I have been having a strange problem with my 2008 GL-320cdi. I recently had the oil cooler seals fixed by an indy shop and after that the car would stumble at low rpm when warmed up. Its fine when it starts and is cold but once the engine warms up, it begins to stumble. Most noticeable at red lights etc so i have to put the car into neutral which helps quite a bit. However at speeds above 60kmh it runs smooth even when hot. In the cold weather since the engine takes longer to warm up, its better behaved. In addition to this, at the low speeds i have noticed an exhaust smell in the cabin so much so that i have to have the air on recirc. Its way worse with the engine cover removed and using the car.

I was going to take it back to the shop but wanted to see if i could get an idea as to what was going on.

Thanks for any ideas.

Miguk_Saram

Is your check engine light (CEL) on? If so, grab your OBD II reader and pull the codes. They should provide better information as to the cause of your issue.

It could be something as simple as a misfire (fouled spark plugs possibly), or a loose/disconnected hose. But you should pull the codes first.

The exhaust smell is likely a side effect of the stumbling (running too rich or lean). Once you correct the stumbling, the odor is likely to go away.

samer

Thanks for your input. It cant be spark plugs (its a diesel)
i had to go and borrow a obd reader.

So two codes came up P0401 (EGR A flow insufficient detected) and P0544 (Exhaust gas sensor circuit bank 1.

Could the EGR valve have failed? If so why the intermittent issue ony at low rpm and operating temps.