Travis Lytle wrote:
>
> I have a 95 dak with about 50,000 miles. I think I am in need of a new cat
> but not for sure. When in gear going down the road it seems make like a
> knockin or ping noise or maybe even just a hole in the cat noise. I pretty
> sure its the cat but not positive because I've been to busy to crawl under
> there and look. But while out of gear and rev the engine a couple times
> the noise is completely gone! Is this normal of a hole in cats? or would
> it possible be something else? This is been going on for quit a while now
> and I'm just now getting around to fixing it thanks to those 10 hour days,
> 6 day a week at work. Last night was about the first time I think I could
> get on it in 2nd and have the backend loosen up a little. It's been a
> while since I could light them up like that. So I know there is something
> going wrong here. The computer is just giving me code 55. Although I did
> replace the cap, rotor, and plugs(platinum) about a month ago and drive
> very frequently about 100 miles a day, it didn't seem to stop the noise nor
> the getup and go problem.
>
> Any idea guys?
>
> Yes I'm using Bocsh platinum plugs and had the same noise before as I did
> with these. Kind of weird though I have more getup and go with these than
> the others but I guess that cap and rotor could have help too and a
> different set of plugs would be better?
>
> Travis Lytle
Travis,
I have exactly the noise same you describe. My truck is a 95 SLT 4X4
5.2L Auto, 3.90SG. I also have dual pipes and a flowmaster three chamber
muffler and I can still hear the noise. I have thoughly checked the
exhaust with a hose to my ear and have found no leaks. I have had my
wife put the truck in gear with the emergency brake on to see if I could
simulate the driving conditions and listen, but no luck. I have also had
the muffler shop check it they could find no leaks or problems. They say
that if the Cat has a cracked honeycomb you can tell by hitting the Cat
with your hand WHEN IT IS COLD. The muffler shop and the dealer both
said that these trucks have a "tinny" exhaust sound. If you drive with
the sliding rear window open you can hear the noise pretty good. I am
almost beginning to think that maybe it is just the way the truck
sounds.
I also think that it could be the EGR valve leaking maybe it would be
more severe under load.Plus the goofy pipe that feeds it, that thing
probably has a sound all to itself. Anyway Ill keep listening and
looking. Taking the Cat out is a good idea though, that would settle it.
Please let me know if you figure it out.
Don,
95 SLT 4X4 5.2mag, auto,
3.90 limited slip,
flowmaster cat back duals
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