I have a 05 GTO and love it for the most part, but there is one major problem. In first and second gear, when reaching around 4500RPM, the car begins to buck. Today, I slowly drove the car up to 5000RPM in 1st and nothing happened. Shifted again to second and slowly brought it up to 4500RPM and the car started jerking back and forth. I watched the tack, and the RPM needle jumps up by 500RPM intervals or so instead of smoothly going up. The traction control WAS off, even tested it by breaking the tires loose and no, nothing kicked in. Taking it to the dealer, but does anyone know what this might be? It usually happens in 1st gear too if I don't just leisurely drive it up to high RPM's....usually happens if I give it ~50-60%+ WOT. The car has less than 500 miles on it, so I thought it might be something in the computer, but others have not had this problem. Also, don't know about in other gears, because I have not taken it up that high....I learned about this problem by accident when I forgot to shift out of second and the car started bucking....scared the crap outta me....

 

137 views and not a single reply....AWESOME!! Can I hi5 someone?? No, really....

 

Check to see if the coil packs and spark wires are secured properly. Sounds like an ignition issue.

 

Thats very weird, especially on a stock car with low miles. The LS2 has done exactly this 5000-5500 rpm bucking on supercharged cars, because of a MAF related patch in the tuning. Luckily this can be programmed around.

Not sure about a stock one doing it though.

 

Because the milage is so low (500mi) it's probably an electrical gremlin that the dealer will sort through under warranty. Please post back when you find out so we can have an outcome to this thread. ~Joshua

 

Just got back from the dealer:

Guy working on the car said he checked the ignition and everything else on the car and that he couldn't find anything. Went for a test drive and it did it right off the bat (for those of you who don't know, the car will buck when driven harder than normal). He says that I'm probably just letting the clutch out too fast and the car is trying to catch itself or whatnot. Only problem I have with this is that how do people race these cars on the dragstrip if you can't disengage the clutch quickly? I am by NO means just dropping the clutch, but I pivot my ankle upwards quickly. I don't think a car with 400HP should have a problem like this, especially since I'm not dropping the clutch anywhere NEAR the speed I would be if I was racing.

Also, in the past I have driven the car slowly up to ~4k RPM. Up to that point the car worked fine, and then around the 4K mark the car started doing it....there was absolutely NO clutch engagement at the time, the car just started doing it (I believe this was in first gear). Also, I have driven the car where the car will ride fine for a second or two and THEN start to buck, well after the clutch has been disengaged. Anyone know what's going on?

 

Have your dealer check the fuel pressure (while driving the car). It sounds like a load based issue , so it could be a fuel or ignition issue. Other than that, find somebody in your area with HP tuners. Get them to log all of your input sensors to see if one is acting funky.

 

Here is what someone suggested over at ls1gto.com:


And my response to this was....

It maybe nothing major or detrimental to the car, but it should NOT perform like this. I know some people have different standards on their cars. Honestly, there's been a clicking noise coming from the steering wheel area that I have overlooked, nothing major. Hell, even if the car rattled and squeaked a bit I wouldn't give two *****....I bought the car more for it's comfort, but more importantly, the wonderful engine. When something on the car is negatively influencing the true performance on the car, I find it comepletely unacceptable. When I'm driving, I don't want the car jerking back and forth, scaring the cr@p outta my passengers and making ME feel insecure in the car. I would have GLADLY taken the A4 over the M6 if I knew this was GM's standard(s)....


What do you guys think? Could it be the electronic throttle control? Next time I go down I will ask them about the fuel pressure while driving and see if they can hook it up. I don't want ANYONE touching the car but the dealership, just in case I have to take this to court to have my car declared a Lemon (if such measures need to be taken).

 

The first place i would check is the TPS on the electronic throttle control.
The TPS is heavily relied upon on ETC.
Hook A-tap or another scanner to it and check the TPS for a steady range.
If the readings jump around when the pedal gets close to the floor, or any where it is a bad sensor.
Hope that helps.

 

My LS2 Performs fine... And it does not "buck" like yours... Very oddd....

^^^^GOOD ADVICE^^^^

 

Does it behave that way only at part throttle? What about at WOT? Can you go WOT to redline and shift without incurring the bucking?

 

A friends GTO had an ignition problem, ls2, m6. It took about 4 weeks to fix and about $4k worth of labor and parts. His was covered under warranty. Hope yours doesn't take this long to fix.