Engine / transmission Stumble ?
Thread Starter
Melting Slicks
Joined: Jun 2001
Posts: 2,400
Likes: 1
From: Woodbridge Va
Engine / transmission Stumble ?
When i'm crusing at 65mph (sometimes higher speeds) 
and sometimes at lower speeds, I hear the car stumble. Its not a misfire, but more like a 'surge'. The RPMs will bounce up 200 for a bit then it returns to where it was before. Sometimes, it will flutter up and down while driving in the city. It sounds like its dropping in and out of overdrive, but I'm not 100% sure. It also happens sometimes if I hit a bump on the interstate.
The problem started back in 2003, but it went away for a while. I noticed it again off and on in 2004. In 2006 I took it in for a leak around the seals and it turned out to be something more than a leak, so they rebuilt the transmission. Since the rebuild, I have replaced plugs and wires, when I first noticed the problem again. It also throws no codes. I don't know what else to check.
Btw: Its an A4.
and sometimes at lower speeds, I hear the car stumble. Its not a misfire, but more like a 'surge'. The RPMs will bounce up 200 for a bit then it returns to where it was before. Sometimes, it will flutter up and down while driving in the city. It sounds like its dropping in and out of overdrive, but I'm not 100% sure. It also happens sometimes if I hit a bump on the interstate.The problem started back in 2003, but it went away for a while. I noticed it again off and on in 2004. In 2006 I took it in for a leak around the seals and it turned out to be something more than a leak, so they rebuilt the transmission. Since the rebuild, I have replaced plugs and wires, when I first noticed the problem again. It also throws no codes. I don't know what else to check.
Btw: Its an A4.
Last edited by Lowcash; Mar 12, 2008 at 08:34 PM.
Thread Starter
Melting Slicks
Joined: Jun 2001
Posts: 2,400
Likes: 1
From: Woodbridge Va
Pro
Joined: Jan 2006
Posts: 643
Likes: 2
From: Alexandria Northern Virginia
Low C,
I would think its an air related thing, just from that description. Seems to be going up in rpm, not dipping. Check the intake air bridge for a loose connection at the "clamp" (that is an overstatement, more of a POS cheapo way to save a buck). I had that go bad on my 04 and it was throwing codes (conditions were met to throw it). If you have oil all in your intake, I would suspect this is leaking. If you go over a bump, you can get a leak. For the code to throw, there has to be a sustained difference in MAF and MAP sensor readings of more than 50% volume. In other words, a quick bump makes it leak, it surges, then it settles back down and the "seal" is made again.
My unsolicited .23 1/2 cents.
Cassidy
I would think its an air related thing, just from that description. Seems to be going up in rpm, not dipping. Check the intake air bridge for a loose connection at the "clamp" (that is an overstatement, more of a POS cheapo way to save a buck). I had that go bad on my 04 and it was throwing codes (conditions were met to throw it). If you have oil all in your intake, I would suspect this is leaking. If you go over a bump, you can get a leak. For the code to throw, there has to be a sustained difference in MAF and MAP sensor readings of more than 50% volume. In other words, a quick bump makes it leak, it surges, then it settles back down and the "seal" is made again.
My unsolicited .23 1/2 cents.
Cassidy
Thread Starter
Melting Slicks
Joined: Jun 2001
Posts: 2,400
Likes: 1
From: Woodbridge Va
Thread Starter
Melting Slicks
Joined: Jun 2001
Posts: 2,400
Likes: 1
From: Woodbridge Va
Low C,
I would think its an air related thing, just from that description. Seems to be going up in rpm, not dipping. Check the intake air bridge for a loose connection at the "clamp" (that is an overstatement, more of a POS cheapo way to save a buck). I had that go bad on my 04 and it was throwing codes (conditions were met to throw it). If you have oil all in your intake, I would suspect this is leaking. If you go over a bump, you can get a leak. For the code to throw, there has to be a sustained difference in MAF and MAP sensor readings of more than 50% volume. In other words, a quick bump makes it leak, it surges, then it settles back down and the "seal" is made again.
My unsolicited .23 1/2 cents.
Cassidy
I would think its an air related thing, just from that description. Seems to be going up in rpm, not dipping. Check the intake air bridge for a loose connection at the "clamp" (that is an overstatement, more of a POS cheapo way to save a buck). I had that go bad on my 04 and it was throwing codes (conditions were met to throw it). If you have oil all in your intake, I would suspect this is leaking. If you go over a bump, you can get a leak. For the code to throw, there has to be a sustained difference in MAF and MAP sensor readings of more than 50% volume. In other words, a quick bump makes it leak, it surges, then it settles back down and the "seal" is made again.
My unsolicited .23 1/2 cents.
Cassidy
Clean MAF
Check grounds
Check air intake clamps
Sounds like my weekend to do list is filling up.
Thanks for all the input on what to check out. I would hate to take it to a dealership and then they cannot replicate the problem without going for a spin down I-495.
Thread Starter
Melting Slicks
Joined: Jun 2001
Posts: 2,400
Likes: 1
From: Woodbridge Va
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Pro
Joined: Nov 2005
Posts: 626
Likes: 0
From: Fresno CA
Me Too
My car seems to have this issue also. Mostly I notice it at highway speeds. I've found that if I set it on cruise control it doesn't seem to happen, the 200 rpm surging will stop. I was starting to think it may be something with TPS getting old or? I'm interested to see if cleaning the MAF works. I have changed to a cold air intake and it has got me thinking!
Instructor
Joined: Apr 2008
Posts: 139
Likes: 0
From: Cameron North Carolina
I've got the same problem. Just bought a 99 vert A4 with an after market cold air intake on it. Will check for leaks, also had a vacume line leak which further caused it to jump in rpms. Should check those also.
