09 LS3 Low Speed Bucking with Manual Trans
 

Just wondering if this is a common situation with the 09 LS3 at speeds just above idle in first gear.

If I'm stuck in traffic and am in 1st, the car will drive smoothly at idle at around 5 mph. But if I try to increase the speed a little to 6 to 11 mph, it's impossible to drive smoothly because the engine will buck. At 12 mph it's smooth again.

I've also noticed that in neutral you can not hold any RPM between idle ~600 rpm and 1100 rpm. The slightest touch of the gas the engine goes from idle up to 1100 rpm.

Any ideas? Also, the engine is totally stock.

It is a guess on my part, but I expect that the jump you speak of has something to do with the calibration transitioning from a pure lookup table to using the MAF sensor. The 6 speed manual CTSv I’m driving does a similar thing. I find that while creeping in heavy traffic or expressway backups, that shifting to a higher gear can help by keep the rpm in the more linear area of the throttle. JMHO

yep my 08 does the same thing. even when it was stock

Has anyone had any luck in getting this problem fixed under warranty. My 05 LS2 never had this problem.

Heck, I thought it was just me. I can't get it to smooth out using the throttle unless I go ahead and launch. Owned manuals all my life, never had this issue.

are they all Z51 cars?

Mine is a Z51 but don't think that makes any difference since it's an engine problem between 600 and 1100 rpm not a transmission problem.

My 08 never did it. Wont disconnecting the battery for a while reset the ecu? I would try that.

Mine does it as well, but it's mainly on decel when the rpms are low in gear....say perhaps when I'm crusing slowly in stop and go traffic in 2nd gear, and don't feel like going down to first. The on and off motion with the gas pedal will cause it to buck a bit.......but it may be attributed to just being a bit low rpm wise in gear. I know exactly what you're talking about, and your post title definitely caught my eye. Mine is a Z51 as well, don't know if the lower gearing in the trans would attribute to that much of a difference over the base gear ratios.

-Brian

A stock car should run as smooth as silk. I'd take it to the dealer.

My automatic does the same thing. I have taken it to two different dealers and they don't know how to fix it. Mine is s base model and stock.

This was my original post on the issue.
http://forums.corvetteforum.com/c6-t...seriously.html



Bobby

I would disconnect the battery for a few mins then reconnect make sure HVAC controls and radio are both off. Then start car and don't touch throttle for a few mins. See if that helps at all. Don't forget to re-index the windows after all that.

oneblackvette

What do you think disconnecting the battery would accomplish?

My gut feeling is that what I'm experiencing is going to be considered normal by the dealer like kk5zc reported. Mine has done this since new and I now have around 9000 miles on it.

Mine has done this as well since the very first day I received 'er with one mile on the odometer. A tune helped to help fix the issue for the most part but occaisionally I still notice a very slight bucking at low speeds as described earlier. I've tried the battery disconnect a few times and it never worked.

Mine does that too, 2k9 z51. was wondering if that could just be the way the throttle -by-wire works, going from idle state to min throttle... dealer was first doubting there really was anything perceptible, then couldn't find anything wrong.
I guess it's just the way it is then :)

Definitely not acceptable. Generally speaking this condition "could" be caused by: late ignition timing, vacuum leak, insufficient enrichment, faulty throttle positioning switch, faulty throttle motor/ module. I would start with a scan of the TPS and look for linearity or lack there of in its output signal. Your dealer can inst, a temporary monitor to scan and record your driving events. This data might reveal the specific problem. Good luck.........

My '08 Z51 MZ6 has never done this, and I am frequently in traffic letting the car pull itself along in 1st, 2nd, or 3rd gear or applying very light throttle.

I have a 09 C6 M6 Z51....it does the same thing...I ride in 2nd and it resolves the problem..but yes its there

'09 C6 Z51 6 spd manual - No issues with bucking in traffic in 1st gear between idle and 15mph, unless, I make it buck myself :)

I can pretty much hold it at any speed without a problem.

09C6Coupe,

If you are in neutral, can you hold any rpm between idle and 1100 rpm? Like say 850 rpm? Mine jumps from idle to 1100 rpm. Can not hold anything in between.