This may be a long shot. So, I have a Renault Megane 2, with a 2.0l Diesel engine with theoretical 150hp and 340Nm of torque.

The thing that worries me is that when I push the pedal, it just takes some time to respond. It's like lack of torque and only get reasonable power at 2200 rpm, while in the specs sheet of the engine, I should get and appreciable power starting at 1500 rpm.

What can be causing the lag (and loss of power maybe)?

(Additional information: At idle, the engine vibrates, quite a bit, but don't know if it has something to with the problem above.)

EDIT 1 :
@Pᴀᴜʟsᴛᴇʀ2 The car is from 2007 with the 2.0L Diesel M9R. It has 150 000 km (~93 000 miles).

EDIT 2 :
Went to a specialized workshop and they found an error on the on-board computer. It indicated that it was a malfunction of some magnetic valve of the turbo. They cleaned the valve and nothing changed. They even tried a new valve without any success. Their conclusion was that the problem is from the turbo not functioning properly, which means either get this turbo fixed or get a new one.

Is it possible that the problem isn't the turbo?

  • By "Megane 2" you're suggesting the model year for it is 2002-2009? Please give us the exact year? And this is the 2.0L Diesel M9R engine? How many miles on the vehicle? – Pᴀᴜʟsᴛᴇʀ2 Aug 12 '16 at 10:45
  • Do you get any black smoke from the tailpipe when you step on the accelerator pedal? When was the last time you changed out the air filter? Do you hear excessive turbo whine? How has performance changed over time? Did it used to be peppier? have you ever tried running a fuel injector cleaner through the engine? When was the last time the fuel filter(s) were changed? – Pᴀᴜʟsᴛᴇʀ2 Aug 12 '16 at 11:36
  • @Pᴀᴜʟsᴛᴇʀ2 All the filter have been changed in the last 1 000 km. I got the car about a year ago, and have tried to figure out why it has this behavior. I already tried to running fuel injector cleaner but nothing changed. I drive other cars and even though they have less power, they feel peppier than mine. – Syphirint Aug 12 '16 at 11:49
  • Are the other cars you're comparing gasoline (petrol) motors? – Pᴀᴜʟsᴛᴇʀ2 Aug 12 '16 at 11:56
  • @Pᴀᴜʟsᴛᴇʀ2 If there is black smoke, I haven't seen it, unless you floor it and pass the 3 000 rpm, and even then, it's residual. All the cars are diesel. – Syphirint Aug 12 '16 at 11:56

Have someone check your catalytic converter. Blocked converters on my pickup caused a power loss so severe thought it was the tranny. It had an engine code saying a trans, component was slipping, and a constant check engine light. My radiator overflow would also percolate when I turned off the engine. All the symptoms disappeared after the cats were corrected. Power like a champ again.

  • I doubt a Renault Megane Diesel has any catalytic converters. – SteveRacer Aug 13 '16 at 4:30

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