Corvette Action Center - The ultimate online hub of Corvette news and information! Click here to go to the Corvette Forums!


Supporting Vendors / Dealers - Supporting Membership - Advertising Information - Corvette Amazon Shop
Page 1 of 17 1234511 ... LastLast
Results 1 to 15 of 255
  1. #1
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default sort of stumble at idle

    Since returning from CruiseFest I have had a little issue with a little stumble at idle, sometimes when it stumbles it shakes the whole car, sometimes it just slightly noticeable. Only when in gear and only at idle. If I rev up just past idle 800-900 RPM stumble goes away. (makes me think IAC, but why only under load?)

    Here's what I have done/checked:

    #1 no SES light and have checked, No codes set either in History or Current.

    #2 I have changed Fuel Filter, opti, plugs, wires, WP, Injectors all within the last 6k miles

    #3 Cleaned TB and MAF within the last 8K.

    Things I haven't done that might be problem solvers. Remove and clean IAC and/or EGR.

    Other thing, this morning after I put my AutoXray 6000 on to check for codes and scanned the computer for what it was doing...the stumble went away. What's up with that? Not to say it won't return but I was shocked that it went away like that.

    Any suggestions/comments/help? I am thinking that I should go ahead and remove the IAC and the EGR and clean them, can't hurt either way.
    ​Formerly known as Toms01
    2007 Atomic Orange
    Coupe Cashmere/black interior

    2005 CruiseFest Attendee (Bowling Green, KY)
    2007 CruiseFest Attendee (Colorado Springs, CO)
    2008 CruiseFest Attendee (Cleveland, OH)

    2010 Cruisefest Attendee(Effingham, IL)
    2011 CruiseFest Attendee(Effingham, IL)

    Visit the members GuestMap and show us where you live.

    http://www.mapservices.org/myguestmap/map/TomBachman

    link to thread
    http://www.corvetteactioncenter.com/...c-members.html





  2. #2
    Member JimBobC4's Avatar
    Join Date
    Aug 2004
    Location
    Canton Ga
    Posts
    343
    Corvette(s)
    1995 Dark Red 6spd Convertible

    Default

    edited post. I just reread and saw the opti was new.

  3. #3
    Member gmjunkie's Avatar
    Join Date
    Nov 2004
    Location
    Old Fort NC/Vero Beach FL
    Posts
    5,320
    Corvette(s)
    03 Z-51,78 L82 Coupe

    Default

    Quote Originally Posted by toms94 View Post
    Since returning from CruiseFest I have had a little issue with a little stumble at idle, sometimes when it stumbles it shakes the whole car, sometimes it just slightly noticeable......... I am thinking that I should go ahead and remove the IAC and the EGR and clean them, can't hurt either way.
    I'd definitely be checking the EGR,Tom!!Sometimes after a Long Warm Up,Like a Long Cruse to Ohio and back!! A chunk of Carbon can break loose from seaming No where and be bouncing around in the EGR and is too Large to get through the pintail!!Sometimes they can hold them close to wide Open and they won't idle at all,or sometimes just a small piece gets between the pintail and seat,holding it open a Milli Fraction!! And will cause your Exact problem!! Basically acts like a small vacuum leak (Because,Thats what it is,Only Internal and Not External!!) and will cause your Exact problem!! Some auto parts stores sell a special gasket for the EGR that will eliminate this problem for around $12-$14,but I usually make my own for about $6-$7!! Consists of 2 EGR gaskets with a Stainless screen sandwiched between them on the Exhaust Port of the EGR!!
    junk!!
    "WARNING"
    The views and opinions of this forum user might not be suitable for others, this user may appear to be heavily over-medicated, under medicated, intoxicated, listening to the voices in his head or just plain being an ass, so some viewers may be offended!~!!!
    www.gmjunkie.com
    Founding Member: 10 Corvettes Anonymous


  4. #4
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    Junk, what is required to clean the EGR out?manually digging cr@p out or is there some kind of spray cleaner?

    BTW, Thanks.

    OK, I did a search and found out that you recommend a carb or throttle body cleaner. How about the stainless screen, where do you get that?

  5. #5
    Member gmjunkie's Avatar
    Join Date
    Nov 2004
    Location
    Old Fort NC/Vero Beach FL
    Posts
    5,320
    Corvette(s)
    03 Z-51,78 L82 Coupe

    Default

    Quote Originally Posted by toms94 View Post
    Junk, what is required to clean the EGR out?manually digging cr@p out or is there some kind of spray cleaner?

    BTW, Thanks.

    OK, I did a search and found out that you recommend a carb or throttle body cleaner. How about the stainless screen, where do you get that?
    I get the screen at my local True Value hardware store!!On 4.3's and some V8's I can use a stainless faucet screen!! Others like yours,I believe it will need to be a little larger and more rectangular,if they don't have any Bulk Stainless screen,(They usually do!!) I'll buy a Cheap Stainless Food strainer and cut it up!! I've even been known to Steal one from the Wife!! Depending on the size,I can usually get enough screen out of one to make 6-7 of them!!This is a purdy common problem on vehicles that set around allot or has higher miles!! You can put a New EGR on them,but they'll just do it again if a screen is not place!!

    PS Screen must be Stainless!! Aluminum or Reg Steel will burn out very Quickly!!
    junk!!
    "WARNING"
    The views and opinions of this forum user might not be suitable for others, this user may appear to be heavily over-medicated, under medicated, intoxicated, listening to the voices in his head or just plain being an ass, so some viewers may be offended!~!!!
    www.gmjunkie.com
    Founding Member: 10 Corvettes Anonymous


  6. #6
    Member LT4man's Avatar
    Join Date
    Jun 2003
    Location
    Chicago
    Posts
    2,400
    Corvette(s)
    96 Collectors Edition LT4

    Default

    Tom, I only run "Top Tier" gasoline.

    Running a container of Techron every couple tankfuls certainly will help.

    Just a couple of ideas for you down the line.

    SAVE THE


    An attendee at all the CruiseFests including the one which never happened.


    Autosig (Shadow) A

  7. #7
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    I try to only run Shell, Mobil, P66, BP in mine. I also run a bottle of Techron through mine about every fourth tank or so.

    Junk, I'll pick up some stainless screen next time I'm in the "big city".

  8. #8
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    Ended up going to the big city today and picked up a food strainer (nobody had stainless screen stock). I have the gaskets coming in the morning, so I'll try to get this accomplished tomorrow....notice I said try. I'm going to remove the IAC and clean that out as well.

    We had wind damage to the roof back in May, insurance tells us that we need a new roof, the roofers were supposed to start August 11, they show up today and say we got moved up and they are starting tomorrow morning! So I have to get the pickup and car out of the garage before they get here, so they have access to the driveway for their truck to dump the tear off shingles into. I won't be able to use the driveway at all tomorrow, so I need to get the wifes' car out, so I can let the vette down. There are some drawbacks to having the vette on a lift and the other two vehicles in there with it, sometimes it's just not very handy to have to move things around.

  9. #9
    Member gmjunkie's Avatar
    Join Date
    Nov 2004
    Location
    Old Fort NC/Vero Beach FL
    Posts
    5,320
    Corvette(s)
    03 Z-51,78 L82 Coupe

    Default

    Quote Originally Posted by toms94 View Post
    Ended up going to the big city today and picked up a food strainer (nobody had stainless screen stock). I have the gaskets coming in the morning, so I'll try to get this accomplished tomorrow....notice I said try. I'm going to remove the IAC and clean that out as well.

    We had wind damage to the roof back in May, insurance tells us that we need a new roof, the roofers were supposed to start August 11, they show up today and say we got moved up and they are starting tomorrow morning! So I have to get the pickup and car out of the garage before they get here, so they have access to the driveway for their truck to dump the tear off shingles into. I won't be able to use the driveway at all tomorrow, so I need to get the wifes' car out, so I can let the vette down. There are some drawbacks to having the vette on a lift and the other two vehicles in there with it, sometimes it's just not very handy to have to move things around.
    Tom when you get the EGR off, Try this before you start cleaning and messing with the pintail!! It will give you a Idea if it's leaking before you start!! (Bottom part of the post!!)

    Starting problem.
    junk!!
    "WARNING"
    The views and opinions of this forum user might not be suitable for others, this user may appear to be heavily over-medicated, under medicated, intoxicated, listening to the voices in his head or just plain being an ass, so some viewers may be offended!~!!!
    www.gmjunkie.com
    Founding Member: 10 Corvettes Anonymous


  10. #10
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    Quote Originally Posted by gmjunkie View Post
    Tom when you get the EGR off, Try this before you start cleaning and messing with the pintail!! It will give you a Idea if it's leaking before you start!! (Bottom part of the post!!)

    Starting problem.
    Thanks Junk, I will do that first. Hey when I stopped in at the parts place today they were asking me if was planning to break the studs off when I removed the EGR valve....I think they were just pulling my leg, but should I soak those nuts down overnight before trying to take these off, or am I not going to have problems?

  11. #11
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    Pulled the EGR off and it was cruddy but when I sprayed the cleaner in it didn't leak or seep around the pintle. I went ahead and clean it up pretty good. I stopped up to the parts store to get my gaskets and they ordered the wrong ones...Oh well I wasn't going anywhere in the Vette today any how.

    I also took the time to remove the IAC and clean it up as well, it wasn't too bad either, but I gave it a good cleaning too. I think I'll pull the intake air tube and clean the TB while I am at it.

  12. #12
    Moderator Toms007's Avatar
    Join Date
    Sep 2004
    Location
    Southwest Kansas
    Posts
    5,213
    Corvette(s)
    2007 Atomic Orange Coupe

    Default

    Well, it appears that my problem is gone. I got the TB cleaned yesterday and everything re-assembled today and fired it up and no stumble. I'll let you guys know if anything changes.

  13. #13
    Member JimBobC4's Avatar
    Join Date
    Aug 2004
    Location
    Canton Ga
    Posts
    343
    Corvette(s)
    1995 Dark Red 6spd Convertible

    Default

    Quote Originally Posted by toms94 View Post
    Pulled the EGR off and it was cruddy but when I sprayed the cleaner in it didn't leak or seep around the pintle. I went ahead and clean it up pretty good. I stopped up to the parts store to get my gaskets and they ordered the wrong ones...Oh well I wasn't going anywhere in the Vette today any how.

    I also took the time to remove the IAC and clean it up as well, it wasn't too bad either, but I gave it a good cleaning too. I think I'll pull the intake air tube and clean the TB while I am at it.

    How do you clean out the IAC ? is it safe to just squirt some carb cleaner in it ?

  14. #14
    Member LT4man's Avatar
    Join Date
    Jun 2003
    Location
    Chicago
    Posts
    2,400
    Corvette(s)
    96 Collectors Edition LT4

    Default

    Tom, that's pretty cool. Looks like you got to the root of your problem.

    As a maintenance idea, depending on the miles you put on in a year, what you did should probably be done about every 15-20k.

    As a side note, I NEVER clean the EGR valve on my LT4.

    Can the class tell me why?

    SAVE THE

  15. #15
    Member LT4man's Avatar
    Join Date
    Jun 2003
    Location
    Chicago
    Posts
    2,400
    Corvette(s)
    96 Collectors Edition LT4

    Default

    Quote Originally Posted by JimBobC4 View Post
    How do you clean out the IAC ? is it safe to just aquirt some carb cleaner in it ?
    I would suggest removing the Idle Air Control motor. Made sure it faces down (electrical connector facing up) and spray either carb cleaner or throttle body cleaner onto it. Use a soft bristle toothbrush or a rag to wipe the carbon off the pintle. Spray a little into the TB. Reinstall the unit and you should be good to go!

    SAVE THE

Page 1 of 17 1234511 ... LastLast

Similar Threads

  1. timed vs manifold vacuum
    By resto75 in forum C3 Technical and Performance
    Replies: 25
    Last Post: 03-29-09, 01:16 PM
  2. Ported Vs. Manifold Source: Vacuum Advance
    By photovette in forum C3 Technical and Performance
    Replies: 26
    Last Post: 01-22-09, 09:01 PM
  3. Off Idle stumble
    By TriTown in forum C4 Technical and Performance
    Replies: 3
    Last Post: 03-21-05, 08:52 AM
  4. Off Idle Stumble - A Holley Carb Review
    By Roy in forum C3 Technical and Performance
    Replies: 5
    Last Post: 12-22-03, 01:06 PM
  5. High Idle Problem
    By Demps in forum C4 Corvette ZR-1
    Replies: 3
    Last Post: 01-24-03, 10:32 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© CORVETTE is a registered trademark of the General Motors Corporation & Chevrolet Motor Division.  Neither Chevrolet Motor Division nor any subsidiaries of GM© shall bear any responsibility for CorvetteActionCenter.com content, comments, or advertising. CorvetteActionCenter.com is independent from GM© and is not affiliated with, sponsored or supported by GM©.  Copyright/trademark/sales mark infringements are not intended, or implied.  All Rights Reserved