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I will give a brief introduction to this problem. Few months ago after catalysator had been rattling along for some time, car suddenly lost half of its power and started stutter on acceleration and making hissing noises. Turned out that one of the catalysator cells had worked itself loose and clogged the cat. This caused lack of power and hissing noises caused by EGR hoses coming loose. I took off 1 of the 2 cat cells, and car worked fine. Now it has started to do the same thing. The one remaining catalysator cell is installed in a way which makes it almost impossible for it to come loose. So I'm thinking it might not be the case this time. However, car has lost about almost half of its 130 horsepower, and any revs over 3000 will detach of the EGR hoses by itself, earlier this was caused by the backpressure of clogged cat. Car also stutters on acceleration, works somewhat decently on low revs but anything over 2000 ish RPM or WOT, and car won't really accelerate.
The hose that keeps coming loose is the lower one of the black hoses attached to brass pipe, on lower part of the black circle:
Anyone have idea what could be the culprit, does the EGR system itself get clogged somehow? I've changed the T-piece under inlet manifold but it didn't have any effect. Also I couldn't spot any splits in the EGR hoses, even though they are in a difficult locations to reach.
Hi. Have you tried to block the EGR valve with a blocking plate? I had similar problem with my mk1 Mondeo and solved the problem with blocking the EGR valve The car was like brand new after and is still going strong
I blocked the hose leading to EGR valve, and also the EGR valve pipe which the hose attaches to. This didn't really help, the car still keeps shooting out the EGR solenoid valve hose and makes hissing sounds. It might've added few more bhp though, not sure. I think I'll have to remove the 1 last cell from catalysator just in case as clogged cat & exhaust gas back pressure caused this last time. But I'm also fairly sure there is still a vacuum leak somewhere as car will make slight hissing sounds when accelerating.
Whats the best and safest way to find vacuum leaks, spray water into the vacuum hoses?
Mk1 Mondeo 2.0 Zetec stuttering and lack of power
The car was like brand new after and is still going strong 
