Afternoon everyone hope this group can help. I have a Ford focus ST TDCI 2015. It has a misfire. Injectors have been tested and are all good. It has been mapped and the map is good. DPF delete and egr delete and I have done a egr blanking plate. When driving uphill normally in 4th and the car is struggling to get above 2000rpm the exhaust has a ripple sound then it suddenly clears, gets louder and the misfire goes away. Blockage in the exhaust causing the misfire? Any advice would be greatly appreciated

i am still learning about cars but my first thought is maybe do a compression test?

i could be wrong so hopefully more experienced people will come along

by doing a compression test, i believe you will know which cylinder is firing

16 hours ago, James2296Red said:

Afternoon everyone hope this group can help. I have a Ford focus ST TDCI 2015. It has a misfire. Injectors have been tested and are all good. It has been mapped and the map is good. DPF delete and egr delete and I have done a egr blanking plate.

How do you know the mapping is good? Do you have the power and torque graphs from the dyno both before and the after the mapping was performed? Which specialist did perform the remapping?

Major modification like a full DPF delete (both software and hardware) and an EGR delete (both software and blanking plate) require an appropriate custom written mapping including life data analysis and dyno testing. Writing such a mapping can easily take a specialist a few days to get everything right.

There are too many self-proclaimed specialist that use off the shelf mappings that are just bought from others. Some of them do not even perform life data analysis and dyno testing to fine tune the mapping. In my opinion this should be avoided at all times. I have too many times that an incorrectly performed mapping or an off the shelf mapping resulted in serious problems. Sometimes even engine damage.


In this specific situation I would start looking at all live data to find the probable cause of the problem. You just cannot rely on DTC codes because it is unclear which DTC codes may have been mapped out.

If the custom mapping is preventing a proper diagnosis, it may even be required to put the car back to standard first.

I have to agree with @JW1982 , how do you know the remap is not faulty?

As soon as I read something has been remapped, I lose interest!