Ford Mondeo occasional amber engine light on, and had the glow plug light flash??

I noticed only a few weeks ago, i been getting afew.... what id consider small issues? first time a month ago, i got the car go into limp mode for all of 5 seconds, after being in 3rd gear and dropping to 20mph on a 30mph road? and as quick as that light came up, it went off. 23rd of december, had the aux heater/glow plug/ injector amber light come on flashing, but not having me in limp mode, i had to go shopping for 20 minutes, started the car back up...and it was fine again, And today, again for around 5-7 seconds, the engine light came on, into limp mode, and drops straight out.....is my car going insane, or is it just playing up? any ideas would be good, as I'm off to my mechanic thursday as its booked in for its handbrake cable replacement...i was informed by another mechanic today to just turn on the electrics first, let the lights clear, and the amber engine light stays on, once the cars started, its gone??