2003 Rough Idle / Stall
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 15 of 15
Cadillac DeVille 1985 to 2005 including:
1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, 2003 Rough Idle / Stall in Past Cadillac Vehicle Discussion; I have a 2003 Deville (130,000 mi) with a P0300 Random Misfire code and a P0410 code. I have replaced ...
  1. #1
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    2003 Rough Idle / Stall

    I have a 2003 Deville (130,000 mi) with a P0300 Random Misfire code and a P0410 code. I have replaced the plugs, boots and both coil packs. I cannot find a vacuum leak. Can the Crankshaft Position Sensors fail and not set a code? The car has a serious rough idle, almost stalls after it comes off of high idle. Bad smell from the exhaust as well. Ideas?

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    Quote Originally Posted by Matt R. View Post
    Can the Crankshaft Position Sensors fail and not set a code?
    Absolutely AND rather common. Been there, done that.

  4. #3
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Smile Re: 2003 Rough Idle / Stall

    I figured it out. Vacuum leak at the back of the plenum..

  5. #4
    basscatt's Avatar
    basscatt is online now 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
    9,848

    Re: 2003 Rough Idle / Stall

    Quote Originally Posted by Matt R. View Post
    I figured it out. Vacuum leak at the back of the plenum..
    ----------------------

    also check the FPR - Fuel Pressure Regulator vacuum supply hose -
    it SHOULD be absolutely dry -
    if there is ANY sign of gas in it -
    the FPR diaphragm has a leak -
    and gas is being sucked into the motor -

  6. #5
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Re: 2003 Rough Idle / Stall

    Thanks. I'll check that as well. I'm getting a p0300 code again and I smell gas at start up. Idle is horrible at start up.

  7. #6
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    If you smell gas, the FPR is highly suspect.

  8. #7
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Re: 2003 Rough Idle / Stall

    Fpr is dry...

  9. #8
    basscatt's Avatar
    basscatt is online now 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
    9,848

    Re: 2003 Rough Idle / Stall

    Quote Originally Posted by Matt R. View Post
    Thanks. I'll check that as well. I'm getting a p0300 code again and I smell gas at start up. Idle is horrible at start up.
    ==========================
    P0300 is a generic misfire code -
    our on-board code readers will not display WHICH cylinder/cylinders is/are misfiring -
    only that there IS a misfire -

    take the car to any large auto parts store - they will check your codes for free -

    P0301 is a misfire in cylinder #1 - P0302 is cylinder #2 - P0303 is #3 - etc -

    once you discover WHICH cylinder is misfiring - diagnosis becomes much easier -

  10. #9
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    Quote Originally Posted by Matt R. View Post
    Fpr is dry...
    You did check it with the engine running, didn't you?

  11. #10
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Re: 2003 Rough Idle / Stall

    Yes. I let it run for a few minutes and then pulled the vacuum line off. I have a coil cassette at home, that may be my next step. I had a misfire 302 code last week..

  12. #11
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    The gas smell is worrisome. If you smell gas, there is a leak and that should be priority #1. Worry about the misfire later.

  13. #12
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Re: 2003 Rough Idle / Stall

    Looks like there is a cylinder head kit in my future. The smell must have been a combination of unburned fuel and coolant. She tried to overheat last night on the way home.

  14. #13
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    I would not jump to that conclusion on an '03.
    Check the purge line, WP belt tensioner, coolant level and then do a block test if necessary.

  15. #14
    Matt R. is offline Cadillac Owners Member
    Automobile(s): 2003 Deville
    Join Date
    Nov 2010
    Age
    40
    Posts
    9

    Re: 2003 Rough Idle / Stall

    Coolant in the cylinder explains the rough idle on start up. After a few minutes, it would idle fine. I'll check the items you listed as well, just to be sure. It has 136k on the odometer.

  16. #15
    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
    66
    Posts
    73,326

    Re: 2003 Rough Idle / Stall

    Coolant in the cylinder is a death certificate, but I don't recall you mentioning that before.

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