I recently decided to fit a decat delete pipe and egr blanking kit, had them fitted and obviously the EML light can on and threw codes for egr, but the car ran fine no issues, I’d been busy and not put the mapped file on, until Friday evening, I went to a job Saturday morning and the car had lost the low end torque, you can hear the turbo. I checked with the diagnostic tool and it came up MAF fault, I’ve checked all pipes and connections, I’ve ordered another MAF sensor, incase it has gone bad, anyone had similar issue, I remap cars and never had this with customers cars.

I’m going to run the ori file and see what happens to rule out either a fault with map or fault with MAF sensor 

When modifying the exhaust has the lambda sensor been damaged etc? 

10 minutes ago, Steve Q said:

When modifying the exhaust has the lambda sensor been damaged etc? 

Not that I know of mate, before I ran the mapped file, it was fine, it was 6 days before I ran the file 

Fair enough, was just thinking because the cat had been removed. Was there a sensor in the cat? 

15 minutes ago, Steve Q said:

Fair enough, was just thinking because the cat had been removed. Was there a sensor in the cat? 

Yes mate, I’m going to run the ori file in the morning and see if it solves the MAF but I can’t understand how the map would alter the MAF as it’s the first sensor along the chain

Not sure to be honest. You didn't fit an aftermarket air filter at the same time did you? 

I ask as the additional air coming through the maf sensor might be throwing it off. 

2 minutes ago, Steve Q said:

Not sure to be honest. You didn't fit an aftermarket air filter at the same time did you? 

I ask as the additional air coming through the maf sensor might be throwing it off. 

I fitted a ram air 4weeks prior, I’ve got a new maf sensor coming tomorrow, so I’ll take it from there.

Just now, Ian1975 said:

I fitted a ram air 4weeks prior, I’ve got a new maf sensor coming tomorrow, so I’ll take it from there.

Please keep us posted on how you get on. It could be the ram air causing the issue. Might be worth reverting to stock to see if that cures it.  

Just now, Steve Q said:

Please keep us posted on how you get on. It could be the ram air causing the issue. Might be worth reverting to stock to see if that cures it.  

I will update. Thanks 

Thank you 

On 7/14/2025 at 6:49 PM, Steve Q said:

Not sure to be honest. You didn't fit an aftermarket air filter at the same time did you? 

I ask as the additional air coming through the maf sensor might be throwing it off. 

I fitted a ram air 4weeks prior, I’ve got a new maf sensor coming tomorrow, so I’ll take it from there.

Ive found out the problem out , on the egr delete kit on the back of the main part there is a blanking screw, this had loosened its self, so resulting in massive air leak, fitted a new bolt and the cars spot on now mate 

5 hours ago, Ian1975 said:

I fitted a ram air 4weeks prior, I’ve got a new maf sensor coming tomorrow, so I’ll take it from there.

Ive found out the problem out , on the egr delete kit on the back of the main part there is a blanking screw, this had loosened its self, so resulting in massive air leak, fitted a new bolt and the cars spot on now mate 

Fantastic news, glad it's sorted. Thank you for updating us 🙂 

Thanks Steve 👍