Hello all!

I've been trying to get to the bottom of the jerking/performance problem that my car has been having.

Sometimes, when I turn my car on from a cold start, the revs will keep dipping.

If I put my foot down on the pedal a bit, the revs will drop all the way down with the car making a clunking noise as they reach the bottom, then it will shoot up and begin dropping again.

After about 10 minutes of driving, the problem will suddenly disappear, no gradual changes, it will just suddenly drive fine.

A clip of the uneasy revs can be found below:

Restarting the car doesn't help, I just have to ride the jerking out until it stops.

When filming that video, I noticed some smoke coming out of the right hand side of the engine cover near the right side of the engine so I stopped straight away and turned the engine off soon after.

Also when travelling at speed (e.g 65mph), when putting my foot down relatively hard, the car will begin to accelerate and then start juddering backwards and forwards whilst accelerating. Easing off the pedal remedies this problem.

I've tried disconnecting the MAP sensor and the car drives much better, also feels more performant when accelerating. Soon after disconnecting the MAP sensor the following error codes come on:

P0238 - Turbocharger / Supercharger Boost Sensor A Circuit High

P0488 - Exhaust Gas Recirculation Throttle Control Circuit A Range / Performance

P2141 - Exhaust Gas Recirculation Throttle Control Circuit A Low

After plugging the MAP sensor back in and clearing the codes and a few lucky miles later without the car jerking, error codes P0488 and P2141 both came back on (Exhaust Gas Recirculation).

So basically:

- Car drives better with the MAP sensor disconnected but I get a few error codes after a few miles

- With MAP sensor connected, the car sometimes jerks/judders

- Could be the MAP sensor, or maybe MAF sensor? Also maybe the EGR valve due to Exhaust Gas Recirculation error codes?

Also I don't know whether I should be concerned about the fact that the car drives better with the MAP sensor disconnected, I've heard that it's supposed to degrade performance when disconnected, meaning that the performance of my car with it connected could be lacking but I don't know (a friend of mine said getting up to 60mph in my car was quite slow even with my foot down, getting up to 30mph is fine though).

Any help would be much appreciated on what steps I could take next! Thanks! :D

I've updated my post above with new information I've discovered over the past few weeks.

My DPF has been replaced also so the problem can't really be to do with that.

Thanks! :D

Remove egr give good clean

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I'm going to give this a go next week hopefully, I'll get back to you with how it goes.

Thanks for the advice :)

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I had a look at the EGR and just bought a blanking plate.

The car seems to run pretty much the same with it fitted, still feels dead but I'm not sure if the jerking is gone yet because it hasn't been jerking/juddering for the past week anyway.

Took it to someone who a friend told me about and he took it for a spin, said that the turbo was kicking in late and had no punch, but then after driving it some more he wasn't sure. Looking at the advantages of having an EGR plate fitted, my car drives exactly the same which could suggest that the problem is something else then. Still drives better with the MAP sensor unplugged.

The error lights regarding the EGR have disappeared though which I guess is good.

is there much coke up in the turbo from the egr running poorly or the oil feed pipe to the turbo as these are very prone to clogging up with crap due to lack of servicing then this leads to turbo failure wich the 1.6 tdci are prone for? once the egr is blanked off (solid plate), its classed as totally disabled so you can rule this out of the equation....