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Mild "bucking" under mild acceleration

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Old 06-04-2015, 09:50 PM
  #16  
mgordon18
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Originally Posted by StormRune View Post
Did the bucking only happen under mild acceleration but go away under either normal cruise *you said "yes") or heavy acceleration (you didn't say)?
It happened whenever I gave it any gas to accelerate, a lot or a little. Constant speed or coasting (i.e. slowing down), however, remained smooth.

Originally Posted by StormRune View Post
Could it be the engine mounts at the back of the engine carrier? If you remove the air box you can visually inspect them fairly easily. Even without removing the airbox you can get someone to gun the engine at idle while you watch with the deck lid open and see if it appears you are getting excessive play. The transmission also has mounts but I don't know how hard it is to inspect them.

This is all just a wild-*** guess in the absence of other suggestions, so sorry if it sends you on a wild goose hunt.
I'll make sure to add this to the list of possibilities I hand over to my mechanic tomorrow. Thanks!
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Old 06-04-2015, 09:53 PM
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Originally Posted by extanker View Post
mileage ? everyday driver? old gas? any work done on the car lately ? was it raining that day ? put a pro scan tool on it .it sounds like a miss fire issue which can be caused by many problems ......fuel,ignition ,sensors etc. i would hold off on replacing the engine just yet lol
Mileage: Almost 41K miles
Gas: Less than a week old
No work done on car recently (or ever, pretty much!)
It was not raining.

Wouldn't one HEAR a misfire? Or might it at least throw a light on my dashboard?
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Old 06-04-2015, 10:00 PM
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Originally Posted by TommyV44 View Post
Mike,

I'm not sure what the final verdict was but they replaced my engine no questions asked in about 3 days.

Your problem sounds exactly like mineů.exactly!

I would keep noticing this hesitation that came and went and it happened at speed (highway too) but not always and at all different speeds. They started by telling me it must be the gas but I knew that wasn't it. My tech took my car home for the weekend and told me he noticed that one side of the car was very sooty above the exhaust and there was some kind of a valve problem.

They replaced that engine immediately and the car only had 4,000 miles on it.

That's what happened to me Mike and it might not be at all what's going on with yours but see what they say. If you want to call me you can and I'll send you a PM with my number just let me know. I can probably get my tech to speak with you as well but I'm in Florida now n to NJ so I'd have to coordinate that.

I'm sure he'd remember exactly what it was.

Good Luck.

Tom
PM Sent. Thanks Tom.
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Old 06-06-2015, 12:17 AM
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Got car back from my indy.

Short story is: keep driving and let him know if it happens again. No codes thrown, no smoke... basically no sign that it actually happened at all.

So the jury is still out.
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Old 06-06-2015, 12:58 AM
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The same thing happened to me until my guy took the car home for the weekend.

It was very frustrating since the problem would never present itself when I brought it to the dealer.

Good Luck Mike!

Tom
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Old 06-17-2015, 05:16 PM
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I'm having similar issues on my 06 C2S. It has 120k on it with original clutch. I'm leaning that direction since it didn't throw any codes and I would essentially lose all power, but RPM's would stay fairly constant.
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Old 06-17-2015, 07:35 PM
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When I first got my car 9.5 years and 40K miles ago I experienced this, 2007/8. There was some chat on the boards about this unidentified mysterious behavior so I was not alone. Bottom line: happened twice, never returned. I'm with tech, drive it and see what happens. Ghosts in the Machine and all that. Good luck.
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Old 01-13-2018, 11:09 PM
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Old post but my 65K mile 997S did a stumble twice today. First time ever. Under light acceleration in 1st gear just fell on its face. Still running foot back into pedal and fine. No check engine light or anything unusual otherwise. I hate intermittent stuff as they will never happen when you want it to.
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Old 01-14-2018, 11:02 AM
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Probably bad gas.
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Old 01-14-2018, 06:41 PM
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Bad gas...could very well be. I think the gas in the tank is from early November. I have not been able to drive it much since then. Still has 1/2 tank too. Drove today and as normal so running that out and fill up soon. Thanks.
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Old 01-15-2018, 12:24 AM
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OP here.

2 and a half years later and it's never returned. A ghost indeed. Car has been running great ever since.
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Old 01-15-2018, 12:33 AM
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Originally Posted by mgordon18 View Post
OP here.

2 and a half years later and it's never returned. A ghost indeed. Car has been running great ever since.

This thread (given its outcome) just proves the usual paranoia going around.

Thanks for closing the loop and clearing the air!
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Old 01-20-2018, 03:52 PM
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Originally Posted by JackZ R View Post
Old post but my 65K mile 997S did a stumble twice today. First time ever. Under light acceleration in 1st gear just fell on its face. Still running foot back into pedal and fine. No check engine light or anything unusual otherwise. I hate intermittent stuff as they will never happen when you want it to.
I'm having the same issue, Mostly on the highway in 4th I think @3-4,000 rpms.

I call it hesitating, sputtering.
https://rennlist.com/forums/997-foru...e-floored.html
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