I have a 2002 Renault Scenic 1.9 Diesel. It has been running fine until last week I noticed that sometimes it was not accelerating properly. This has now started to happen frequently irrespective of whether the engine is warm or cold. When you press the accelerator there is no response, so when you take your foot off and press it again the engine picks up as normal. I had the car serviced a couple of months ago and they replaced the glow plugs, etc. Could I need the fuel filter replacing or cleaning ?