Fuel Filter may do that, P1351 its glow plug system error and it help or make possisble to start car when is cold only
When You replaced fuel filter ? Is it freeze osutside on area where You are?

 

thanks, diesel filter about 11months old tried testing glow plugs with meater and they seem ok . Not getting any clicking from the glow plug relay when first trying to start the car , so I have ordered a new one to try ., read some were it could be the throttle pedal sensor ? Any ideas? Main problem with car is intermittently like jerking a bit as if you are taking foot on and off the accelerator. Also have noticed once at the traffic lights when car was in neutral it sounded then like you was revving engin or think it's called hunting. But this is an intermittent problem , pulling hair out as garages around me arnt really interested with it been an intermittent problem . Any ideas? Well tried the glow plug relay , put a new one on still no click but have been told it's not relay a relay more off a control module so not sure if should click or not . Help. ?

 

All about glow plugs and his relay I wrote here, its polish but google may haelp You to translate
https://forum.mitsumaniaki.pl/viewtopic.php?t=107860

But its nothing to engine relate problems, as I wrote above
Glow PLugs are needed when temp is below zero as with -10C its impossible to start cold engine, till -5C its difficult to start but possible, when temp is in plus, You may start that engine even without them,
They are sometimes in use when car start DPF cleaning, ECU then is switching on all the heaters (mirrors, rear window, Glow Plugs), unfortunately is no any indication as this process started (I made LED from Glow Plug relay so sometimes I see when it works)

I would start with replacing fuel filter, its easy