Hi, I have a C270 on an 02 plate, recently the orange glow plug light has been staying on for a little while after start up, theres no problem starting but i have got an intermitent limp home mode problem, basically if i nail it for a few seconds it will go into limp home mode but then after rturning to normal driving it comes back out of that ? Is the glow plug light effecting that? Do the plugs just need changing?