Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

Results 1 to 6 of 6

Thread: '99 engine stumble

  1. #1
    Harry Yarnell is online now Cadillac Owners Enthusiast
    Automobile(s): 2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
    Join Date
    Dec 2004
    Location
    perryman, MD
    Age
    73
    Posts
    883

    '99 engine stumble

    Just bought a beautiful pearl white Deville with unknown history with a nasty engine stumble; not a 'miss', but a chuggle just short of stalling while driving. In neutral, it throttles up just fine, and it starts instantly. When I say it's not a 'miss', I mean the stumble is erratic, as a miss is cyclical. A code 131( O2 sensor) is set, but this all is happening before it goes closed loop, so I don't think that comes into play. Here's what I've done: changed fuel filter, fuel pressure is 46#, glass beaded all 8 plugs, though they looked fine, measured resistance of all 8 wires; all within spec, swapped out ignition module. No change. Thinking of swapping PCM, but isn't there some reprograming required to do this?...and what is it? Anyone got some other ideas?


  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS - 67,500 miles, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    Location
    MD Eastern Shore, Kent Island
    Age
    77
    Posts
    56,870

    Re: '99 engine stumble

    Clean the coils, connectors, contacts, ICM and the ICM ground cable terminals. How old are the plug wires ? Time for a new AC Delco wireset. Use the pre-2000 plug wire diagram in my albums to make sure the proper coil tower is connected to the proper plug.

  4. #3
    Harry Yarnell is online now Cadillac Owners Enthusiast
    Automobile(s): 2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
    Join Date
    Dec 2004
    Location
    perryman, MD
    Age
    73
    Posts
    883

    Re: '99 engine stumble

    As a follow up to this issue, seems it was TWO problems; one may have caused the other. Glass beaded the existing plugs (they looked good before). no help. REPLACED the plugs with new platinum AC's, and the miss (chuggle) was sorta gone, but it had no power; the more you gave it throttle , the more it bogged down, Shifting was also late. Suspect a clogged cat. Up on the lift, and you couldn't get near the cat, as it was so hot. Disconnected the four nuts holding the cat to the header pipe, and a test drive showed it would go like a scalded cat (pun intended). Oh, BTW, the dealer wants $100 to reprogram a replacement computer. As to the code 131, they mention a O2 sensor lean condition in bank 1. Which is bank 1? Front or rear?
    Last edited by Harry Yarnell; 08-08-13 at 03:56 PM.

  5. #4
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS - 67,500 miles, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    Location
    MD Eastern Shore, Kent Island
    Age
    77
    Posts
    56,870

    Re: '99 engine stumble

    Eastern Catalytic drop-in and a pipe clamp.

  6. #5
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    69
    Posts
    82,284

    Re: '99 engine stumble

    Bank 1 is the rear bank.

  7. #6
    Harry Yarnell is online now Cadillac Owners Enthusiast
    Automobile(s): 2005 XLR, '96 eldo,'95 eldo,' 89 eldo,'78 eldo,'11CTS-V
    Join Date
    Dec 2004
    Location
    perryman, MD
    Age
    73
    Posts
    883

    Re: '99 engine stumble

    This clogged cat reminds me of a similar situation years ago with a '74 Cadillac hearse. This vehicle wouldn't get out of its own way, the shifts were late and there was this wheezing sound coming from the exhaust. Back then GM was using a double walled exhaust pipe on some models , why, I don't know, but the inner pipe (or wall) had pulled away from the outer pipe and coiled up like a pretzel inside, effectively closing it off. I don't remember how I discovered that, but I cut out that section of pipe for show and tell...


Bookmarks

Cadillac Posting Rules

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Read about Lincoln | Buick | Kia Forte Forum