Hi guys a few days ago my 1.4 Ford Fiesta tdci started to judder at idle it did this for a few days and then got worse and ended up with warning light and going in to limp mod I did a bit of searching and read that the egr valve mite be faulty so I replaced it with an new on and also a new fuel filter it’s still the same and keeps going into limp mode but can be ok for hours then limp again any ideas on what it could be cheers 

Do you have an obd scanner? Preferably forscan? 

It could also be your maf sensor, glow plugs, o2 sensor, camshaft sensor, DPF or any other major electrical component that is capable of throwing an engine management light and limp mode...

So Iv had it plugged in and said it was the maf just got a brand new one and the same but warning light permanently on 

When you put the new one in did you reset the fault code? 

Yeah it was fine for about 20 mins thanks for the reply’s guys driving me mad 

My recommendation would be to buy a scanner, tunnel rat is the go to on here for forscan, last time I checked they were less than £20 so even if you use it once it'll pay for itself. 

https://tunnelrat-electronics.fwscart.com/WiFi_Modified_ELM327/p4541936_17045473.aspx

 

Then download forscan on your phone. 

Check the glow plug relay pins for corrosion/dirt and gently clean them. I sanded mine down a bit then smeared a light coat of vaseline as i had ran out of the proper grease.

Give the relay head a couple of taps with handle of a screwdriver etc before putting the relay securely back in. It can only go in one way.

I know the relay is in a small black box along with a couple of other relays, next to the car battery on the Mk6.5, 1.6 tdci but i dont know where it is on the 1.4. 

Someone on here may help if they know.

If it still doesn't work, you might want to go further and get the relay checked, get a working one from similar car or get a new one.

If it still dosen't work, at least you have eliminated the glow plug relay being faulty as this is what caused a limp mode on my daughters Fiesta.

Three mechanics tried to fix it with their fancy gadgets but failed because the codes generated were pointing to other things than the relay itself. 

I figured it out myself and its been about 3 years and same fault never came back and i didn't even change the glow plug relay. I just cleaned the relay pins and then started the car. Limp mode gone.