2000 STS w/117K 'Severe Misfire' advice needed please!
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

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

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 13 of 13
Like Tree1Likes
  • 1 Post By Submariner409
Cadillac Seville / Cadillac Eldorado Forum Discussion, 2000 STS w/117K 'Severe Misfire' advice needed please! in Past Cadillac Vehicle Discussion; Good Morning, Had a check engine light (SES) that had been coming on for a while, but car was running ...
  1. #1
    middieblueSTS's Avatar
    middieblueSTS is offline Cadillac Owners Fanatic
    Automobile(s): 2000 STS
    Join Date
    Jan 2008
    Location
    Metro Detroit
    Posts
    102

    2000 STS w/117K 'Severe Misfire' advice needed please!

    Good Morning,

    Had a check engine light (SES) that had been coming on for a while, but car was running fine, until earlier this week... 2000 STS 117K, never have changed plugs.

    Started getting the flashing SES light and car was idling very rough and not running well, even after it heats up. Ran onboard diagnostics and got misfire code P0300 (misfire), and P0410 (Secondary Air Injection). So my suspicion to what was causing the issue was misfire,since it never ran rough before flashing SES came on. Went to autozone and had them run scan and got P0302 (cylinder #2 misfire), and the P0410 again. I replaced #2 plug (OEM Delco) and boot last night. No luck, still idiling very rough, feels like a cylinder is missing under acceleration, and smells like its running rich when I'm outside the car when its running.

    I'm thinking my next step here will be to buy a new front coil pack (cartridge), install, probably do the other 3 front plugs/boots, and then see what happens. If that fixes things and I'm feeling brave I might try my luck at doing the back plugs too (just because they need to be done, but probably not related to this issue). Or maybe take to a shop--looked like there was a lot going on back there.

    Do you guys think this is a good plan of attack/I'm on the right track? Any advice? Any help is much appreciated!

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    basscatt's Avatar
    basscatt is offline Cadillac Owners Master
    Automobile(s): 89 Coupe DeVille, 95 Sedan DeVille, 03 SLS, two 02 DHS's
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    63
    Posts
    9,394

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by middieblueSTS View Post
    Good Morning,

    Had a check engine light (SES) that had been coming on for a while, but car was running fine, until earlier this week... 2000 STS 117K, never have changed plugs.

    Started getting the flashing SES light and car was idling very rough and not running well, even after it heats up. Ran onboard diagnostics and got misfire code P0300 (misfire), and P0410 (Secondary Air Injection). So my suspicion to what was causing the issue was misfire,since it never ran rough before flashing SES came on. Went to autozone and had them run scan and got P0302 (cylinder #2 misfire), and the P0410 again. I replaced #2 plug (OEM Delco) and boot last night. No luck, still idiling very rough, feels like a cylinder is missing under acceleration, and smells like its running rich when I'm outside the car when its running.

    I'm thinking my next step here will be to buy a new front coil pack (cartridge), install, probably do the other 3 front plugs/boots, and then see what happens. If that fixes things and I'm feeling brave I might try my luck at doing the back plugs too (just because they need to be done, but probably not related to this issue). Or maybe take to a shop--looked like there was a lot going on back there.

    Do you guys think this is a good plan of attack/I'm on the right track? Any advice? Any help is much appreciated!
    ---------------------------------
    Do you guys think this is a good plan of attack
    YES -

    I'm on the right track
    YES -

    Any advice?
    coil packs are generally very reliable -
    we usually recommend finding good used units over the big bucks for new -
    either the local junk yard - $25 - or ebay - $75 - new $250+

    the only difference between the front coil pack - and rear coil pack is the color -

    ALL 2000 to 2004 Seville models -
    ALL 2000 to 2002 Eldo models -
    and ALL 2000 to 2003 Deville models - use the same coils -

    here is one for $48 with shipping -
    http://www.ebay.com/itm/CADILLAC-DEV...8695a5&vxp=mtr

    only use ACDelco 41-987 spark plugs -
    there is a rebate of $1.50 each - going on until the end of the month -
    http://www.acdelco.com/pdf/Spark%20P...ate%20form.pdf

    carefully inspect the boots - and springs inside the boots -
    any black lines - or any cracks - replace them -

  4. #3
    fivepointohman is offline Cadillac Owners Member
    Automobile(s): 98 Eldorado ( previously 96 SLS )
    Join Date
    Jul 2013
    Age
    33
    Posts
    44

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    You need to change all the plugs and wires not just one.. That will create a fuel nightmare for the ECM and the banks will all be different.. At that mileage they need it anyways..

  5. #4
    basscatt's Avatar
    basscatt is offline Cadillac Owners Master
    Automobile(s): 89 Coupe DeVille, 95 Sedan DeVille, 03 SLS, two 02 DHS's
    Join Date
    Feb 2004
    Location
    Minnesota
    Age
    63
    Posts
    9,394

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by fivepointohman View Post
    You need to change all the plugs and wires not just one.. That will create a fuel nightmare for the ECM and the banks will all be different.. At that mileage they need it anyways..
    ------------------------
    You need to change all the plugs and wires not just one
    what wires?

  6. #5
    middieblueSTS's Avatar
    middieblueSTS is offline Cadillac Owners Fanatic
    Automobile(s): 2000 STS
    Join Date
    Jan 2008
    Location
    Metro Detroit
    Posts
    102

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by basscatt View Post
    ------------------------
    You need to change all the plugs and wires not just one
    what wires?
    I'm just wanting this car to get me through the winter. If I can avoid doing back plugs w/out issues I probably will.

  7. #6
    Submariner409's Avatar
    Submariner409 is offline If it won't run, slap in a big stereo
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,518

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by fivepointohman View Post
    You need to change all the plugs and wires not just one.. That will create a fuel nightmare for the ECM and the banks will all be different.. At that mileage they need it anyways..
    You need to read up on the significant mechanical differences in Northstar engines and their control/management systems that went into place for the 2000 model year. Apples and oranges.

    ECM went away in ??? 1997 ??? or before. Even your 1998 Eldorado has a PCM, not an ECM.

  8. #7
    Ranger's Avatar
    Ranger is online now Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Location
    Woodstock Ill.
    Age
    66
    Posts
    72,387

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by middieblueSTS View Post
    still idiling very rough, feels like a cylinder is missing under acceleration, and smells like its running rich when I'm outside the car when its running.
    You might also check for a leaky FPR.
    Couldn't hurt to clean the TB either.

  9. #8
    middieblueSTS's Avatar
    middieblueSTS is offline Cadillac Owners Fanatic
    Automobile(s): 2000 STS
    Join Date
    Jan 2008
    Location
    Metro Detroit
    Posts
    102

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Just following up. Replaced front coil pack and plugs and it fixed the issue. Thanks for everyones help!!

  10. #9
    98cadillac is offline Cadillac Owners Fanatic
    Automobile(s): 1998 Cadillac Seville STS
    Join Date
    Feb 2013
    Posts
    306

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Quote Originally Posted by basscatt View Post
    ---------------------------------
    ...
    ALL 1998 to 2004 Seville models -
    ALL 1998 to 2002 Eldo models -
    and ALL 1998 to 2003 Deville models - use the same coils -
    ...
    I'm pretty sure it changed at 2000. My 1998 Seville uses four individual coil packs mounted on top of the engine near the firewall (two wires from each) rather than the cassettes.

  11. #10
    MoistCabbage's Avatar
    MoistCabbage is offline Cadillac Owners 10000+ Posts
    Automobile(s): Crimson 2001 Seville STS, 1990 Seville (RIP)
    Join Date
    Sep 2010
    Location
    East Boston MA.
    Age
    26
    Posts
    20,501
    Coil cassettes came along in '00, and lasted until '04, when they changes to 8 individual COP coil packs.

  12. #11
    Submariner409's Avatar
    Submariner409 is offline If it won't run, slap in a big stereo
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    43,518

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    Looks like basscatt edited his post on coil years ....................
    98cadillac likes this.

  13. #12
    N*Caddy's Avatar
    N*Caddy is offline Cadillac Owners Master
    Automobile(s): 1997 Cadillac STS (BOSE w/AUX In, Massage Seats, URPAS, "Z")
    Join Date
    Nov 2006
    Location
    Toronto, Canada
    Age
    35
    Posts
    6,374

    Re: 2000 STS w/117K 'Severe Misfire' advice needed please!

    You mean even '96 year vehicles had PCM, and probably I can go back up to '93.
    I do believe the '04 Seville (the few made) had gone away from the '00-'03 cassette design. I believe that year had individual coils for each plug.

    Nobody changes just 1 sparkplug (unless we are talking about my lawnmower or snow blower).

  14. #13
    stoveguyy is offline Cadillac Owners Connoisseur
    Automobile(s): 96 STS, 140k
    Join Date
    Aug 2007
    Location
    mpls mn
    Posts
    2,480
    In 04, the seville, xlr, srx, went to the 4 coil, 1 coil module per bank.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting