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Traction control issue or something else?

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Ran a HPDE event yesterday and had a couple of weird issues.
Ran in the am with no issues, went out after lunch and ran 1 session without any issues.
2nd session I was waiting on pre grid, tried to rev the motor a bit and it fell on it's face, got the go ahead and everything was fine. First lap was fine although I heard a a very slight clunk that seemed to come from the rear of the car somewhere along the way. Went into turn 1 and the car acted like the traction control was kicking in, turn 2 was worse, I was running no were near as fast as I had in earlier sessions, slowed down and checked gauges, everything looked fine, continued on going slower and slower and still the rear of the car seemed to be jerking then going back to normal even on the straights. Went to the pits and checked everything I could and saw nothing unusual. Today I pulled the diff cover off and everything looks great but the right wheel bearing was a little rumbling, very little. Pulled it out and it is not perfect but not at all very bad, I will replace but I know that it was not responsible for the actions I was feeling.

Anyone have any ideas or suggestions?
 
Check and make sure both rear wheels sensors are in place and not broken or disconnected.
 
1,022
99
Exp. Type
HPDE
Exp. Level
10-20 Years
Texas
Check all the bushings on your control arms. I had somethings similar when a bushing on a lower control arm failed allowing the rear to move. Also check the upper control arm and diff bushing.
 

TMSBOSS

Spending my pension on car parts and track fees.
7,530
5,247
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
Have you checked for any codes?

Axel runout?

Does the bearing mating surface on the axel look OK?

Like Rick mentioned, check the sensors and connections.

Has this problem occurred since?

We're you running with nannies off?

Any warning lights?

Sounds like an electronics issue. Sensors, connection(s), etc..
 
Here is where I am at, I replaced both rear wheel bearings, they weren't perfect but there was nothing wrong with them either, the axles looked great and are not bent, checked the lower control arms along with the upper and all seems fine. The sensors all looked good. I had the car on the lift and we shook, pushed, pulled and bounced and could see nothing.
Took the car for a couple of drives, pushing as hard as I dared on the street, turning the wheel back and forth quickly trying to feel if anything felt loose, the car felt perfectly normal.
The only issue I had was the first one I mentioned in the original post, 6 times I started the car while it was at operating temp all of which I would blip the throttle a couple of times, 3 of the 6 times started it just went flat, the last time I blipped the throttle 3 times, it got a little better on the second blip, a little more on the third and seemed normal on the 4th blip.
I was running at the track and last night with all the nannies on. No warning lights or check engine lights.
Any ideas???

Thanks, John
 

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