charm Posted July 14, 2009 Share Posted July 14, 2009 As if there aren't enough hesitation threads already... I'm trying to diagnose mine and I'm wondering if something I noticed wasn't the problem. It's a 2000 OBW auto tranny 155,000 miles. The engine was completely resealed with new timing belt and just about everything else about 25k ago by a well respected Subie shop. I replaced the cats right after that with ones that have since died. I'll finally be replacing them with bosals in the next couple weeks. Allegedly, there is a very low rate of warranty returns on these cats and I can get them for half the price of the factory cats. I might be taking a chance here, but to save $500, I'm willing. The CEL for the cats is still on and yes, it is the cats, there is no doubt about it! New O2 sensors front and rear. Spark plug wires have more than 25k on them because, well, that's when I bought the car and I haven't put new ones on. Could be plugs and wires. The part that has me curious is, right before the hesitation started, I was driving on the freeway when it first hesitated (only time it's done it at freeway speed) and the check engine light flashed at me. I pulled the codes today and still only have my 420 code. The hesitation appears to only occur at low speeds. It feels like the car has no power. Like I mentioned above, it has happened only once at high speed and came on suddenly. Thoughts? Link to comment Share on other sites More sharing options...
nipper Posted July 14, 2009 Share Posted July 14, 2009 Are the cats clogged? Clogged cats can make any car a gutless wonder. What condition is the end of the spark plugs wires in? If the cats are failed your going to have a 420 untill the cats are replaced. Link to comment Share on other sites More sharing options...
charm Posted July 14, 2009 Author Share Posted July 14, 2009 I'm certain the cats are done. So you think the hesitation and the cats are related? I can't tell you what the cats look like, I haven't looked at them. I can say that the O2 sensors check out good as new which is good since one is 14 months old and the other is 2 months old. I'm due for emissions in August so I have no choice but to have the cats replaced. I'll do it next week and hope that they're the problem. Man I hate the place that replaced my cats with these hunks of crap!!!! Link to comment Share on other sites More sharing options...
nipper Posted July 14, 2009 Share Posted July 14, 2009 Lets do this. Hit the cats with your hands when they are cold, do they rattle? Spend 19.00 on a engine vacume gauge. tell us exactly what it says and what it is doing. It is an under utilized tool that can tell you so much. http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm Where did the O2 snesors come from? How do you know the cats are good? Link to comment Share on other sites More sharing options...
charm Posted July 14, 2009 Author Share Posted July 14, 2009 The cats are NOT good. They are bad. They O2 sensors, both OEM, were analyzed by the shop. The results, plus P0420 code, point directly towards the cats. I trust the shop. If they're saying cats, it's the cats. Serves me right for going with the cheapest place. A few weeks ago I was under the car and banged on a few things just to check 'em out (while I was down there). Everything sounded solid then. Can't say they do now. I'm heading out for a vacation tonight so hopefully I won't destroy my car on this road trip. I'll pick up a vacuum gauge when I get back. Is there is specific vacuum line you hook it up to? Link to comment Share on other sites More sharing options...
nipper Posted July 14, 2009 Share Posted July 14, 2009 Any vacume line that you can trace back to the intake manifold is good. nipper Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 14, 2009 Share Posted July 14, 2009 Gut the cat and see if that fixes it. Can't hurt if you're gonna replace them anyway. Link to comment Share on other sites More sharing options...
nipper Posted July 14, 2009 Share Posted July 14, 2009 Gut the cat and see if that fixes it. Can't hurt if you're gonna replace them anyway. Normally I would not agree, but since it is already broken, you cant make it worse (especially since they are getting replaced). nipper Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 14, 2009 Share Posted July 14, 2009 Normally I would not agree, but since it is already broken, you cant make it worse (especially since they are getting replaced). nipper Yeah, I don't normally recommend that "fix", but given the circumstances, I don't see how it would hurt to try it. Could just be something simple like a vacuum leak too so check all the hoses for splits. Link to comment Share on other sites More sharing options...
Log1call Posted July 15, 2009 Share Posted July 15, 2009 I don't think gutting the cats will get rid of the code. It shouldn't. The ecu is expecting to see a slower rate of swing out of the rear sensor than the front sensor. If the cats aren't working, or have been gutted, the swing rate is going to be the same front and rear, which is what the ecu is reporting at the moment. I'd be trying to find out what is causing the cats to be polluted, then I'd be trying to burn them clean before replacing them. They can recover f the conditions are returned to normal and they haven't been polluted too badly, or by some specific compounds. I don't suppose your mechanics could have used an engine sealing compound that wasn't cat/O2 friendly? Link to comment Share on other sites More sharing options...
nipper Posted July 15, 2009 Share Posted July 15, 2009 Not trying to get rid of the codes, trying to restore performance (for now). Clearing out a clogged cat will do that. nipper Link to comment Share on other sites More sharing options...
charm Posted July 22, 2009 Author Share Posted July 22, 2009 Replaced air cleaner, fuel filter, and ran a can of seafoam last night. The cats are being replaced as I type. The seafoam seems to have triggered a misfire on the #3 cylinder. I'm hoping that some gunk just fouled a plug. Forgive my laziness but which plugs to buy? I know to buy copper and nothing fancy. I know to buy OEM wires. Where? Is it significantly less via the internet vs. the stealership? Link to comment Share on other sites More sharing options...
nipper Posted July 22, 2009 Share Posted July 22, 2009 Dont always just dismiss the dealer for parts, they can sometimes be very competative in prices. I go to 1stsubaru.com for parts, plugs you have to look it up to see which ones you take (avoid champion) but they can be had anywhere. Just go by what is in your owners manual. nipper Link to comment Share on other sites More sharing options...
charm Posted July 22, 2009 Author Share Posted July 22, 2009 Owners manual? What is this wonderous device you speak of? I was recalling there was a brand of plug to avoid and you answered that well...Champion. I'll go with NGKs and the OEM wires. Still need to pick up a vacuum gauge and check my vacuum lines. Upon visual inspection, everything looked good. But eyes can only tell so much. Link to comment Share on other sites More sharing options...
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