2007 Pontiac Solstice - car jerks when brakes are applied

I still expect this to be a brake problem. But for purposes of discussion, here’s an alternative to brakes, just another of my many off-beat wild guesses :wink:

I had a jerking problem with my Corolla one time. I noticed it mostly when slowing down and turning corners in neighborhood driving; i.e. at slower speeds. It turned out to be a fuel injection problem. Here’s why.

Say you are going along at a constant speed, gas is being injected to keep you going, then as you slow down to turn or come to a stop sign and slow down, instead of what you might think that a little less gas gets injected but still some gas at least; instead what happens w/most cars, the engine computer will completely turn off all the injectors so no gas at all is injected. That’s done to improve mpg. After all no gas at all is needed to just coast along.

But if that no-gas-condition continues all the way to where the car stops, the engine could stall. So the engine computer monitors the situation as the car slows and turns the gas back on before the engine stalls out. The problem that can cause jerking is when the gas is turned back on. In some cases too much gas gets injected at that point, which causes the car to jerk. That can be due to the injectors not metering the fuel correctly, b/c they are gummed up and sticking, etc. It’s harder to meter a small amount of fuel than a large amount, so problems with gummed up injectors tends to show up at slow speeds.

I was able to completely solve it with a couple of injector cleaning treatments. It’s also important to verify the engine idle rpm is correct, both for warm and cold coolant conditions.

The Art of the Guess, By George

Two days is hardly enough time to duplicate, diagnose and repair a cold start drivability problem especially if the engine was hot the first day when dropped off.

This could be as simple as a dirty throttle body but one can’t jump to conclusions. The standard procedure is to observe the problem, diagnose the problem, repair and confirm the repair. This can’t be done in a day and a half. If you put pressure on the shop they may return the car to you unrepaired with “unable to duplicate” response.

For some customers the throttle body would be cleaned gratis with “let me know if that helps” but for others thing must be thorough.

My car shakes like mad until I hit the brakes.

I got my car back from the dealership on Tuesday, the 23rd. They kept my car for a week, they checked the brake system, alignment & transmission. They were not able to replicate the problem, everything check out perfect, ran perfect on every test drive regardless of the time of day, no codes so I picked it up & has been running fine. The mystery continues.

Cars can be a mystery indeed. My truck started acting up a couple months ago, shaking like crazy when the engine was cold, like it was missing. The exhaust gasses from the tailpipe also felt like it was sputtering and missing. So I took the air cleaner off, removed all the vacuum lines and inspected those. Made sure the choke was choking and the idle-up was idling up on the correct cam position. Checked all the vacuum operated devices for leaks, all were ok. I couldn’t find anything wrong at all.

So I fiddled with all the various gadgets on the engine and still couldn’t discover a single thing wrong. So I put it all back together and now it runs perfectly … lol … I have no idea what I did to improve things.

Anyway, glad you are back on the road with working brakes.

My car did the jerking again yesterday afternoon. I drove it as close to the dealership as I could because the jerking became progressively worse the more I drove it. I pulled into a gas station & had my Service Advisor meet me there so he could drive w/me. He immediately knew why it was jerking, he said Solstice are built to do this as a “safety warning” to avoid damage to the motor.

He said, they hooked up my car to the computer & read the torque value & wiggled one of the Camshaft Actuator Solenoids & the readings were all over the place.

It is bad Camshaft Actuator Solenoid, one had a shortage & was completely fried - the other wasn’t fried but it was close to going bad. He said he is sure once they replace both, the problem will be solved . . . . I really hope so.

Thank you all for the comments & advice - I really appreciate all of them.

Thanks for the feedback. Thats a new one on me, feedback helps us all.

Thanks @Solis for the feedback!

That part is involved with the variable valve timing (vvt) function, and if it failed it definitely could cause the car to perform poorly. vvt is a newer way engine designers use to increase performance and still get good mpg, but it adds add’l complications and complexity and so reliability is the compromise. You might find the follow u-tube video of interest. Best of luck.

@GeorgeSanJose - The video makes it looks like a repair that is not too complicated - I guess that’s why it was only $355.96 - $103.76 for the 2 parts & $243.90 for labor. I was expecting him to say it was going to be like $1,800 or more so I cannot complain about the amount.

The description of the work on the invoice is: “High Resistance in Intake & Exhaust CamShaft Solenoids. Tested & Replaced both Intake and Exhaust, both had high resistance - Code: P0013.”

I drove into work this morning & everything sounded & felt normal again, the little pull that I felt when the car was slowing down was no longer there, no more jerking so I am pretty confident that replacing those 2 parts solved the problem.

The car shakes a little when at a complete stop; I was told that I eventually need to have the motor mounts replaced.

My Service Advisor said since I am the only person that drives the car & has always done the maintenance, it should last me for as long as I want to keep it & willing to repair it so I am going to drive it until the wheels fall off because I really do like my car & it’s in excellent condition, no one believes it is 9 years old. It has had few repairs here & there, nothing really major, it has been a great car & can’t beat the gas mileage on it.

Again, many thanks to all of you - www.cartalk.com is saved to my Favorites.

Glad you got your car back on the road and purring like a kitten again. And for a bargain price. Good for you!

Hello to all, found this thread cause I googled a similar problem am having with my 2009 Pontiac G6. When am drive over 35 mph and suddenly break hard my cars tranny will jerk every time is switch’s gears. I then have to pull over turn the car off for a few minutes and it runs fine again. Any suggestions greatly appreciated thanks

Is the Check Engine Light lit-up?

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I know this is a stretch but it could be an intermittent vacuum leak in the brake booster that only manifests when the brake pedal is depressed.

I did not get involved in the original discussion but that part about the service advisor saying that Solstices are designed to do this as a “safety warning” is amusing…a lot amusing.

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No it’s not on

I’m have the same problem! Hoping it’s something simple, just replace the catalyst converter, thought maybe it would fix the sensors. It doesn’t have anymore sensors on but still doing the brake jerking. I hope you were able to fix your car.