01 Pontiac Firebird 3.8 loud at the pipes when cranking but becomes quieter as it warms up

Viewing 1 reply thread
  • Author
    Posts
    • #11273 Reply
      Anonymous
      Inactive

      Here’s another 3.8 doing what they do best..01 Pontiac firebird, has been missing at cruising speeds gradually increasing with temp. and while putting under load,I noticed when first cranked it’s rather loud back at the pipes and quietens as it warms up, eventually the rpm’s will drop,with it sometimes stalling, then having to let it cool for a few, and thus the cycle starts all over,initially it had a 0420? and I replaced the o2’s and a bunch of other stuff, this fixed the code I guess , it hasn’t come back on, but the problems are worse……how bout it? should I make a boat anchor out of her? or go on and change the cat?

    • #13917 Reply
      Protech
      Guest

      Everything you describe- code P0420, stumbling at highway speeds, worse the hotter it gets, noisey exhaust etc points to the CATALYTIC CONVERTER. All, that is, except the stalling. I suppose if the exhaust backs up enough it could cause it to die out, but that is not very common. Check the EGR valve operation first. If it is open a little it would give these conditions also.

Viewing 1 reply thread
Reply To: 01 Pontiac Firebird 3.8 loud at the pipes when cranking but becomes quieter as it warms up
Your information:





<a href="" title="" rel="" target=""> <blockquote cite=""> <code> <pre class=""> <em> <strong> <del datetime="" cite=""> <ins datetime="" cite=""> <ul> <ol start=""> <li> <img src="" border="" alt="" height="" width="">