Subject: 95% sure it's clogged cats Author: kiwijochen : member since June, 2006 : 2000 posts Posted on: 2008-11-27 11:58:49

If your catalytic converters are clogged, it'll create your symptoms.

A 10 year old car - likely to have failed cats.
My friend had same symptoms and new cats fixed it.

Also: at that age, give the Idle Control Valve a clean. I had idle problems, whereby the idle would drop then rise again, and my ICV was very clogged and stiff.

A spray with carb cleaner to dissolve the gunk freed up the ICV and then everything was great afterwards.
The ICV is easily accessible on the front top of the engine, just where the air intake goes through the MAF.


Another problem I had with my 540i was missfiring on 1 cylinder due to a partially failed coil. but only on idle. As soon as the motor revved, no more misfiring. We detected which coil it was by doing a smooth running test and monitoring the adaptation values. A new coil fixed that problem.

But if you have a whole bank failing, it'll be the cat on that side which is clogged up.

Replace BOTH cats at the same time, it'll make a phenomenal difference.

• Major engine headache.....long sorry - cfin 2008-11-27 05:07:11 (405 views)
  • Its running.... - cfin 2008-12-01 22:57:41 (160 views)
  • 95% sure it's clogged cats - kiwijochen 2008-11-27 11:58:49 (322 views)
    • Re: 95% sure it's clogged cats - cfin 2008-11-30 05:24:50 (157 views)
      • Re: 95% sure it's clogged cats - bolkow105 2008-11-30 23:04:08 (135 views)
        • Re: 95% sure it's clogged cats - cfin 2008-12-01 02:03:35 (147 views)
          • Re: 95% sure it's clogged cats - kiwijochen 2008-12-01 13:38:05 (156 views)
          • Guess it won't help.... - bolkow105 2008-12-01 11:14:13 (133 views)
            • Re: Guess it won't help.... - stephen2008 2009-09-04 23:22:46 (7 views)
            • Re: Guess it won't help.... - cfin 2008-12-01 20:24:36 (163 views)
              • Follow-up to the 'problem' (nt) - cfin 2008-12-10 04:02:54 (126 views)
                • Re: Follow-up to the 'problem' - cfin 2008-12-10 04:40:05 (154 views)