This is gonna take a bit of explaining.........I've got a 2007 renault trafic 115dci, it started suddenly dropping power then a second later sort itself out generally around 70mph and mainly on long uphill duel carriageways. I took it to a mechanic who checked the injectors as it's done 115k. He did a leak down test and resistance test etc, but they are fine. Got it back, he said there are no fault codes and it drove perfect for 24hrs then it started playing up again, particularly now at pulling away!?! So I took it back and he serviced it. Still shit so took it back again! He said he caught a glimpse if a fault code and changed the Maf. I got it back Friday and within 10mins was fucking about again but now back at 70mph. Needed it for work today and it's just got worse and worse. I'm not getting any dash lights come up or plumes of smoke, and it will drive but I'll be doing 70 and start going up a hill and it'll just drop to 60 even with the throttle not moving!! Can anyone help as I'm gonna burn the fucker soon!

Chopping it in for a new van is not an option so need to fix it.

 

Blocked cat? If you bang it with your fist is it rattling?

 

Ok I'll try that - it's just done 100fucking annoying miles so I may let it cool down a bit first lol!

If it is and I gut the cats will is cause any problems?

 

Will be fine on a diesel as there is no exhaust gas monitoring etc. I would be tempted just to do it anyway to rule it out!

 

I think I will - just had a peak under the van - I take it the cat is up at the back of the block?

 

It's quite possible, most newish vehicles have them mounted straight after the exhaust manifold.

 

Found it - straight after the turbo can't get my hams round to bash it but popped the bonnet and revved the engine - rattle city! Now gotta take a day off to remove the bastard! Looks a bitch of a job

 

Hopefully that's what's causing it then!

 

I really hope so - it does seem the logical answer now you've pointed it out!