Search



Go Back   MustangForums.com > Ford Mustang Tech > 4.6L (1996-2004 Modular) Mustang > SVT Forums
Sign in using an external account
Register Forgot Password?
Search

Welcome to Mustang Forums!
Welcome to Mustang Forums.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!


Reply
 
 
 
 
Thread Tools Search this Thread
Old 11-06-2013, 09:07 PM   #1
djcondo
2nd Gear Member
 
Join Date: Sep 2007
Location:
Posts: 280
Default 99 cobra shakes durring acceleration

Hey all,
Just got a 99 cobra and i notice that it shakes a little under acceleration. If i rev the car there is no vibration whatsoever but when i am back in gear and accelerating it shakes. I have already checked the driveshaft u joints and they seem fine and have found and replaced one cross axis joint. The car has 165k on it..

Also there is a slight clunk in the front end somewhere when hitting the brakes hard or it is sometimes heard when turning

Let me know please, I am new to the cobra world
This ad is not displayed to registered or logged-in members.
Register your free account today and become a member on Mustang Forums!
djcondo is offline   Reply With Quote
Old 11-09-2013, 03:25 AM   #2
JC316
4th Gear Member
 
JC316's Avatar
 
Join Date: May 2009
Vehicle: 1997 Cobra
Location: DFW, TX
Posts: 1,878
Default

There are a lot of things to check, my money is on a motor mount, especially with 165k. Check the motor mounts, the transmission mount, possibly a wheel bearing, possibly the other CV shaft.
__________________
1998 Formula Firebird M6.
Guide to installing a Mark VIII engine in a 96+GT
JC316 is offline   Reply With Quote
Old 11-11-2013, 06:42 PM   #3
djcondo
2nd Gear Member
 
Join Date: Sep 2007
Location:
Posts: 280
Default

Ok so I found out what the clunk was but still have the driveline vib. The bell housing was coming into contact with the K member brace. I threw a washer on the brace and no more clunk but still a vim under harder accel. The trans mount seems real tight i can not move the tail of the trans
djcondo is offline   Reply With Quote
Old 11-11-2013, 10:21 PM   #4
JC316
4th Gear Member
 
JC316's Avatar
 
Join Date: May 2009
Vehicle: 1997 Cobra
Location: DFW, TX
Posts: 1,878
Default

Quote:
Originally Posted by djcondo View Post
Ok so I found out what the clunk was but still have the driveline vib. The bell housing was coming into contact with the K member brace. I threw a washer on the brace and no more clunk but still a vim under harder accel. The trans mount seems real tight i can not move the tail of the trans
I'm absolutely certain it's the motor mount now. If it's hitting that brace, then the mount is broken and needs to be replaced.
__________________
1998 Formula Firebird M6.
Guide to installing a Mark VIII engine in a 96+GT
JC316 is offline   Reply With Quote
Old 11-12-2013, 06:18 PM   #5
djcondo
2nd Gear Member
 
Join Date: Sep 2007
Location:
Posts: 280
Default

how much space should be between the two?
djcondo is offline   Reply With Quote
Old 11-13-2013, 12:37 AM   #6
JC316
4th Gear Member
 
JC316's Avatar
 
Join Date: May 2009
Vehicle: 1997 Cobra
Location: DFW, TX
Posts: 1,878
Default

Quote:
Originally Posted by djcondo View Post
how much space should be between the two?
I have no idea, but I do know that the bellhousing isn't supposed to touch. Shaking during acceleration + the bellhousing hitting that brace = busted motor mount. There is no question about it. Put a jack under the oil pan, with a block of wood to spread out the pressure and lift it up. If the mounts are good then the engine wont go up.
__________________
1998 Formula Firebird M6.
Guide to installing a Mark VIII engine in a 96+GT
JC316 is offline   Reply With Quote
Old 11-13-2013, 09:00 AM   #7
Steve@Tasca
Former Sponsor
 
Join Date: Sep 2013
Vehicle: 2002, SVT Focus
Location: Minnesota
Posts: 177
Default

I'd also suggest taking a real good look at the IRS mounts and everything out back, as these things get old they're going to run into more issues with worn out IRS mounts and shafts.

Last edited by Steve@Tasca; 11-13-2013 at 09:10 AM.
Steve@Tasca is offline   Reply With Quote
Old 11-18-2013, 07:24 PM   #8
djcondo
2nd Gear Member
 
Join Date: Sep 2007
Location:
Posts: 280
Default

Well threw in some motor mounts and that solved the driveline vibe. They are so trashed that the oil pan was touching the steering rack. I have seen some junk motor mounts but never this bad. One side had half the rubber gone and when I popped it out chunks of rubber was falling out.

On a side note. I now notice a slight miss/ stumble/ shake in rpm between idle and about 3000 ish. I don't feel it really when driving but when reving I feel it. Time to figure that one out. Let me know if you smart fellows know what to check with that.
djcondo is offline   Reply With Quote
Old 11-19-2013, 08:57 AM   #9
Steve@Tasca
Former Sponsor
 
Join Date: Sep 2013
Vehicle: 2002, SVT Focus
Location: Minnesota
Posts: 177
Default

Maybe try getting the real wheels safely and solidly off the ground and then run it through the gears and see if it does it with the car off the ground.
Steve@Tasca is offline   Reply With Quote
Old 11-19-2013, 09:13 AM   #10
djcondo
2nd Gear Member
 
Join Date: Sep 2007
Location:
Posts: 280
Default

Well it seems like engine running rough not anything related to driveline and spinning. I was going to just pull one plug wire off at idle and see if any one does not make a difference to check my spark/ ignition system
djcondo is offline   Reply With Quote
Old 11-19-2013, 09:13 AM
MustangForums
Ford Mustang




Paid Advertisement

 
 
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Advertising

Featured Sponsors
Vendor Directory
New Sponsors
All times are GMT -5. The time now is 12:31 PM.

© Internet Brands, Inc.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company
Emails Backup