Hi all, having some problems with my 04 Signum 2.0DTI. When it is idle, the rev needle is dropping to about 500rpm and then bouncing back up to 1000rpm repeatedly, and at the same time it feels as though it's punching the engine. It is as if it is trying to stall itself, but it doesn't quite cut out. It has done this ever since I bought the car in November, but the problem wasn't as bad then, it would just do it every so often. At first I used some redex to clean the system, then I had the diesel filter changed, and then after reading many threads from people who had the same problem, I took the car into the garage and told them the problem and suggested they check my vacuum air hose pipes, when the car came back from the garage they had apparently checked all pipes but found no splits or anything unusual, and they said it cant be anything serious so keep driving it until it breaks!
However the problem seemed to sort itself out for a small while. After a recent long trip of about 1500 miles the car is now doing this thing much more, and if I am sat still and the car is doing it for a while it will also start pumping out a lot of smoke. Once it's running it is generally fine, the fuel economy is well over 50mpg, although I have noticed that when I accelerate but then gently release pressure on the accelerator there is a slight jumping or a pull on the engine, it feels as if not enough fuel is getting through possibly? I really need to get the car booked back into the garage but wondered if anyone on here have had the same problem, so I have some idea of what work is needed to be done, and how much the ****** thing will cost!
The only thing I could think it could be is a blockage somewhere in the fuel system. I was driving the car last week when the engine electronics light came on, but then went off after about 3 or 4 miles, but then when I pulled up the car started jumping and the light came back on... then went off, I have since covered about 100 miles and the light has not reappeared, even though the car has been very jumpy, so I'm not sure if the light is linked? Also, when starting the car at the weekend it immediately started jumping and it actually completely stalled itself, it hasn't done this before. I have looked in the engine when it is idle and jumping, and it shakes around the whole engine and exhaust system.
Can anyone help me!?