Page 2 of 5 FirstFirst 12345 LastLast
Results 21 to 40 of 92

HELP ! Bucking and jerking when trying to maintain speed!

This is a discussion on HELP ! Bucking and jerking when trying to maintain speed! within the General Help forums, part of the LSx Technical Help Section category; This seems to be a common problem. My 2000 Z28 auto with 105 thousand miles has been doing the same ...

  1. #21
    Junior Member
    Join Date
    Oct 2010
    Location
    Maryland
    Posts
    10

    black
    2000 Z28

    This seems to be a common problem. My 2000 Z28 auto with 105 thousand miles has been doing the same thing for about a year. First I changed the plugs, checked the fuel pressure (good at idle), changed PCV valve, and replaced the right hand cat with a walker cat. The car still has a mind of its own and inconsistent performance. I have not cleaned the mass air sensor, which has been recommended by many. I was sure the right cat was bad... but I was wrong....(230 dollars wrong). One of the salesmen at SLP said the right cat goes bad 98% of the time. The bog or non responsiveness seems to happen more when the car is dead cold. The car has never quit on me like some of the reports that I have heard from the bad fuel pump guys. I need help too, maybe 02's next???

  2. #22
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Is there a valve in the air system that prevents air being drawn into the header?

  3. #23
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    Quote Originally Posted by 5abivt View Post
    Is there a valve in the air system that prevents air being drawn into the header?
    there are check valves on top of the manifolds.....

  4. #24
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    Quote Originally Posted by AllBlackZ28 View Post
    This seems to be a common problem. My 2000 Z28 auto with 105 thousand miles has been doing the same thing for about a year. First I changed the plugs, checked the fuel pressure (good at idle), changed PCV valve, and replaced the right hand cat with a walker cat. The car still has a mind of its own and inconsistent performance. I have not cleaned the mass air sensor, which has been recommended by many. I was sure the right cat was bad... but I was wrong....(230 dollars wrong). One of the salesmen at SLP said the right cat goes bad 98% of the time. The bog or non responsiveness seems to happen more when the car is dead cold. The car has never quit on me like some of the reports that I have heard from the bad fuel pump guys. I need help too, maybe 02's next???
    if it's doing it when it's completely cold that would almost rule out O2's since they aren't functioning then anyhow. The O2's close the loop once the car comes up to temp. I would look more at cleaning your MAF and look for vacuum leaks. How's your idle?

  5. #25
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    I have A new fuel filter but I'll do that when it's warmer maybe this weekend. I'm heading down now to check for any vacuum leaks on hosed etc and will put the air blockoff plates on if I can find them. Will report back soon!

  6. #26
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    My guess is vacuum leak since you're running lean on only the one bank.

  7. #27
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    Quote Originally Posted by 35th-ANV-SS View Post
    My guess is vacuum leak since you're running lean on only the one bank.
    vacuum leak should effect both banks really because it's letting the intake suck extra air but an exhaust leak will only effect 1.

  8. #28
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Put on the block off plates. I kept the metal piping off the plates so they still can blow air out and so I won't get codes. Here's plug #3 I just pulled to check.


  9. #29
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    you're gonna get codes either way......the pcm will look for changes in the O2 voltages and know that the air pump is not pumping into the exhaust stream. My guess is you'll get a check valve code as if the check valve was clogged up....that's a guess.

    That plug looks like ass.

  10. #30
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Ya definitely rich for sure. There's less than 6k miles on them. Blockoff plates done and ya you're right I'll probably get a code. If things don't change I'll just rebook the air lines after I solve the problem. Checked all the hoses I could find all look to be in decent shape. Going out for a drive now... Going to clean the plugs out when she's hot the. Hit the highway and set the cruise control. Brb

  11. #31
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Been driving 5 mins or so almost fully hot .. No codes or light from air so far
    Last edited by 5abivt; 04-11-2011 at 07:25 PM.

  12. #32
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    No luck got to 80 mph and settled down.. Felt slight hesitation in the pedal and knew it was coming.... Second later I get bucking and jerking I can hear the whole driveline clicking and clanking back and forth. Jetta vr6lol tries to race me.. Slaughter him and am now heading home.

    I know the bank is rich so something is telling PCM to dump morefuel. Headers and cats/y look the same as always I'll spray for leaks when I get under it to change the rims. I'll ask local forum if anyone has an 02 I can plug in with fresh plugs for a drive to see what happens. I'll spray maf cleaner tomorrow if I can remember to buy some on the way home from work.

    All I can think of for now.

  13. #33
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Quote Originally Posted by 0rion View Post
    vacuum leak should effect both banks really because it's letting the intake suck extra air but an exhaust leak will only effect 1.
    Good point. I'll check header bolts tomorrow too to make sure none have loosened. The first o2 was showing the code so I'd imagine it would have to be upstream of the sensor which is all header primaries and up :/

  14. #34
    Junior Member
    Join Date
    Oct 2010
    Location
    Maryland
    Posts
    10

    black
    2000 Z28

    Quote Originally Posted by 0rion View Post
    if it's doing it when it's completely cold that would almost rule out O2's since they aren't functioning then anyhow. The O2's close the loop once the car comes up to temp. I would look more at cleaning your MAF and look for vacuum leaks. How's your idle?
    The idle has been a little rough in the past, right now its ok. I also changed the fuel filter. My only mods are an SLP airbox and a predator tune.

  15. #35
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    Quote Originally Posted by AllBlackZ28 View Post
    The idle has been a little rough in the past, right now its ok. I also changed the fuel filter. My only mods are an SLP airbox and a predator tune.
    start with your MAF sensor....you can buy MAF cleaner at any parts store. It's cheap and will only take a few minutes to do. I would recommend pulling that MAF completely off so you can spray from the front and the back. You'll see 3 little wires with resistors....soak those down really well with that cleaner but don't try to handle them or wipe them with anything because they're very fragile.

  16. #36
    Veteran 0rion's Avatar
    Join Date
    Aug 2005
    Location
    ohio
    Posts
    22,519

    98 Formula
    06 duramax

    Quote Originally Posted by 5abivt View Post
    Good point. I'll check header bolts tomorrow too to make sure none have loosened. The first o2 was showing the code so I'd imagine it would have to be upstream of the sensor which is all header primaries and up :/
    It almost has to be an exhaust leak or just a bad O2. Do you still have your rear O2's? If so you can move them up front. From the looks of that plug I'd bet your O2's are fouled also but it's hard to say if one led to the other. Check everything for leaks and then look at doing something about those O2's. Check a passenger side plug too and make sure it's only on 1 bank and not on both. I've just been going by the lean code that was bank 1 but bank 2 could have some issues also....wouldn't hurt to check a plug.

  17. #37
    Junior Member
    Join Date
    Oct 2010
    Location
    Maryland
    Posts
    10

    black
    2000 Z28

    Smile

    Quote Originally Posted by 0rion View Post
    start with your MAF sensor....you can buy MAF cleaner at any parts store. It's cheap and will only take a few minutes to do. I would recommend pulling that MAF completely off so you can spray from the front and the back. You'll see 3 little wires with resistors....soak those down really well with that cleaner but don't try to handle them or wipe them with anything because they're very fragile.
    Thanks Orion, I'll give it a shot... of MAF cleaner.

  18. #38
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    Allblack does your car do it all the time on the highway?

    Update for me.. I'm on the way to work and late so I'm blasting every car through 3rd gear I figured I'd see if I could flex some muscle. My service engine light popped within 10 mins. On The highway now and no bucking or jerking at all so far :/

  19. #39
    Senior Member
    Join Date
    May 2009
    Location
    Toronto
    Posts
    1,083

    SOM
    2002 SS

    At the very least I have a code i can recheck. Going to buy a code reader tonight and pull the code(s). WIll report back !

  20. #40
    Moderator 35th-ANV-SS's Avatar
    Join Date
    Oct 2008
    Location
    Wherever life takes me
    Posts
    12,465

    Red
    02 35th LE Camaro SS

    Quote Originally Posted by 0rion View Post
    vacuum leak should effect both banks really because it's letting the intake suck extra air but an exhaust leak will only effect 1.
    I agree with you. I was assuming it might be an exhaust leak since there was mention that the exhaust was hit on a speed bump.

Page 2 of 5 FirstFirst 12345 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. How to Maintain Your Android Phone
    By Ed Blown Vert in forum Computers / Gaming
    Replies: 0
    Last Post: 06-27-2012, 03:50 AM
  2. Help: engine bucking @ high end torque
    By abarthle in forum LT1
    Replies: 10
    Last Post: 03-22-2008, 09:08 PM
  3. Help: engine bucking @ high end torque
    By abarthle in forum General Help
    Replies: 1
    Last Post: 03-22-2008, 06:51 AM
  4. easiest to maintain TTM's: black or chrome?
    By mindreaper in forum Wheels and Tires
    Replies: 5
    Last Post: 10-14-2006, 09:46 AM
  5. Bucking when decelerating
    By torridred04gto in forum General Help
    Replies: 0
    Last Post: 08-09-2006, 09:31 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •