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Discussion Starter · #1 ·
Help I have a very strange fault. My Mondeo 2.2tdci feels like it's misfiring randomly at motorway speed. It's almost like fuel starvation. On a 10 mile stretch will occur between 3 and 6 times but only above 60mph.

I have cleaned EGR and replaced fuel filter and still the same.

No fault codes, no loss of power and because it's random I can't replicate the fault.

Any ideas where to go next
 

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dont listen to me, you'll have horsepower and
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Many have had the same issues between 1500rpm and 2000rpm I blanked my egr (cleaning doesn't guarantee its working) this made it 80% better I then seen a boost leak can cause a slight judder so although I didn't find a leak I replaced the boost that comes upto the egr valve and never had a judder since
 

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As above blank the EGR completely to eliminate it. A full blanking plate not one with a hole.

Only above 60mph in what gear? Does using a lower/higher gear affect anything? Temperature related?
 

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Discussion Starter · #4 ·
Hi guys yeah thanks for replies. So it's completely random but predominantly motorway speed. Occurred at 5th and 6th gear 60, 70 and 80 and anything realistically above 2000rpm.

I got RAC out to code read and they picked up an intermittent fault with EGR valve so looking highly likely that's the cause. Will it still pass MOT with it blanked off as its due Thursday? If it will I'll just blank it now if not I'll wait lol
 

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dont listen to me, you'll have horsepower and
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Normally brings on the engine light after around 20-50 miles which will fail an mot so unless you have a code reader to clear the codes just before an mot then wait until afterwards
 

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Discussion Starter · #6 ·
Coincidentally I have found quite a substantial oil leak around the intercooler to inlet manifold pipe. However like I mentioned no noticeable splits or performance drop or smoke however did hear a noticeable whooshing noise under load. Coincidence or potentially the pipe
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Little Megger
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Yep, get that sorted and I bet you've cracked it. Any apparent 'misfiring' (and that's how we interpret the symptom) is due to sudden boost loss when at speed, - not actual loss of boost , but lessening of boost when a split in a boost pipe suddenly opens up under boost pressure, or loose hose connection leaks a bit of boost. Often tell-tale sign of this is oil around the connection.
 

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dont listen to me, you'll have horsepower and
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That part isn't for the mk3 I don't think. But yes thats the common hose for bursting.
Replace with a silicone hose they're much cheaper and last longer. I paid £14 for mine and was still good 5 years later
 

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Discussion Starter · #9 ·
So update I believe with help from every here I have found the cause. Large split in intercooler pipe which was hidden on engine side hence missed my initial inspection. Got a new hose coming tomorrow. Taped split and will test for improvement later. And will update again big tanks to everyone massive help folks
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dont listen to me, you'll have horsepower and
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Is that a mk4 mondeo you have? 2007+)
 

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dont listen to me, you'll have horsepower and
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Ahh that makes sense now... you posted in the mk3 diesel category so very different engine but luckily we've come to a positive conclusion anyway
 

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MEG Corporal
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Looks like the same split that happened on mine. I fitted a silicone hose sourced from ebay as I don't think you can get it on it's own from Ford (comes with the metal piping too)

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