Hi all, I have used this forum to get myself to doing my car, changed flywheel and clutch with the help of this forum, going through all the threads to get as much info as possible, and flywheel and clutch is now spot on. My car would now and then go into limp mode, off and on with ignition and the car is ok again, get home and plug the OBD2 in to it, and nothing. So, I cleaned the EGR valve, change the oil and all the filters ( air, oil and Delphi fuel filter ) put a little bit of Wynn's ejector cleaner in, and the car went as good as new. Now just got home with the glow plug light flashing ( the car didnt go into limp mode ) plugged the OBD2 in, and come up with PO251. Turned the car off and went for a cup of tea, came out, started the car up, idle's very nice, no smoke, took it for a short spin round the block, and it feels like new again, plugged the OBD2 in, and it came up with nothing ???? So, my question is... could my problem dirty connection's on the sensors? A dodgy sensor somewhere? Or something more serious waiting to happen ( the begining of injector problems, even though my car is running nice now ) ????? Any help, tips, advice would be great. Sorry to have wrote half of war and peace, but I have been through all the threads on PO251 and could'nt find the problem I'am having. Thanks Nige.