What can cause an automatic car to suddenly shake and stop?
What can cause an automatic car to suddenly shake and stop?
It happened to my car last week, it got towed to a mechanic and I'm yet to hear back. I don't know a lot about cars, so I'm hoping I'll learn something here and be able to tell if the mechanic tries to rip me off.
The car is a small hatchback automatic Hyundai Getz, 2009, serviced regularly. I've had it for 6 years with no major issues until about a year or so.
Five days ago I was driving through the city for at least 40 minutes when suddenly, while waiting at the lights, the car shook and for a moment I thought it would stall. I stopped on a side street, waited 20 minutes and resumed my journey.
About an hour later I'm on the motorway and it shakes again. I stop on the shoulder, wait, but it's not a safe area. I start again, only now I have the check engine light on my dashboard blinking. I manage to take an exit and my car stops on its own, the oil and battery lights now visible too. Fortunately there is no traffic here so I wait a minute, start again and park it on the shoulder.
Roadside assistance arrives, the mechanic looks at it and finds nothing wrong with it other than a fuel sensor which is an issue I've had for several years now. We get it towed to a mechanic but they were closing shop by the time I arrived. Before closing the shop mechanic says that at a glance he doesn't see anything, but notes the oil looks very clean.
I've never had the car shake like this. The last time it failed me was early this year, when it overheated during a very hot day, but it didn't shake. I've had the thermostat repaired since as well as a minor coolant leak.
Congrats, you've read this far. Thoughts?
Flashing check engine light means you have a severe misfire.
Probably a coil pack
That could definitely do that. Had that happen to my GTI; I pulled over as soon as I was able to and parked the car. I checked on an OBD II reader, and the light and shaking was caused by misfiring. I replaced all the coil packs, cleared the code, and it's been fine since.
I'm not mechanical in any way but it sounds very similar to what happened to me. It turned out to be some issue with the transmission. There is something called overdrive or something like that where when you go in 4th gear it engages and you get better highway fuel economy. The problem was it would engage but would get stuck and not disengage which would stall the engine (and shake the car violently) when coming to a stop. I took it to a mechanic and they gave me an option. Fix it for 2000 or disconnect it for 100. I disconnected it and I lost maybe 1-2mpg while driving freeway. Some cars have a button to turn off overdrive so you could try that if yours does.
I just looked up your owners manual and you have a switch on your shifter knob to turn off overdrive.
That sounds like the torque converter lockup clutch. The torque converter is a fluid coupling between the engine and transmission. It will always have some slip. In the 80s they started putting clutches in them to get those 2 mpg you described. Yours must not be disengaging properly, I've never seen one fail like that.
Yeah like I said I am dumb when it comes to cars and this was years ago so I may misremember. All I know is that if I got my car up over around 50mph it would shake violently and stall when I stopped. Then if it sat for 10-20 minutes it would be ok again (until it got in 4th again). I do know they disabled something that reduced my mpg slightly and I never had the issue again for the 2 years I still had the car. Again I don't remember 100% but I think he literally just unplugged a cable. Charged me 75 for diagnostics and 25 for labor.
misfiring, could be coils, plugs, injectors, could be worse (like a bad piston could be blown engine, not unusual for a Hyundai) unlikely fuel pump IMO.
It might be a misfire on one of the cylinders. Try to find somebody with a scanner. It would be interesting to see what comes up
I'm a mobile plant mechanic, but would it run fine before driving?
As in idling and reving?
Knowing that would help diagnose between drivelin issues or engine issues.
Transmission could be fucked or the engine is getting hot and seizing.
Yes, letting it idle and revving wouldn't make it shake. The first mechanic tested that for about 15 minutes. The engine was cold by the time he arrived though.
Hmm, seems drive related then so i would say transmission torque converter perhaps. They cause shaking and stall out engines. Or perhaps kickback valve.
Like a lot of people here, my first thought is misfire, which means either plugs, cables, or coils/coilpack.
My second thought is it could be a vacuum leak.
I've reading a bit after all these answers. I figure coils or plugs would show up on a scan, which the roadside mechanic did and only turned up the already known fuel sensor issue, as I mentioned on the post.
I'm starting to get the feeling it might be something transmission / torque related, which I hope is not the case as it sounds very expensive.
You are the first one suggesting vacuum leak, will keep in mind. Cheers
Yeah, a couple months back I was doing some work on my car and when I was done I did a test start and it started right up. The next morning though it wouldn't start. After giving it a little gas I could get it to...idle, per say, but it sounded terrible. Like Satan spray-shitting hammers and nails into a sheet-metal toilet. At that point though I was able to look in the engine bay with the car running and I could hear an audible hissing - the vacuum line going to the brake booster snapped in two. It must've been torqued weird when I was moving the intake manifold around. I rigged it back together, it started up great, and I went straight to the hardware store to replace the hose
It's not possible to guess with certainty, but my guess is a failing ignition coil pack. The oil and battery lights are just because the engine was off.
I have a 20yo car with a bad torque converter that I'm dragging my feet in replacing.
It shakes at stops and to get it to stop shaking I shift it to neutral. Your car is in the shop so you can't really make that test.
Fuel sensors can cause some funky things though. Give fuel when it shouldn't and not give when it should. It will cause misfires that way.
Driving with faulty parts will cause other systems to fail. It's usually better to replace things sooner rather than later.
Blinking check engine = pull over and call a tow truck. You'll do even more damage by continuing. As for shaking, it could be a bunch of things and I'm not going to speculate beyond what other people have commented.
Traction control can cause the tires to refuse to move if you’re on a slippery surface like snow.
One of these will immediately tell you with a free app
He said he already scanned it, so it won't tell him anything he doesn't already know. I actually do have one of those though, albiet with some other Chinese branding. It's not very durable as I've already had to replace it, but it's cheap so who cares? It won't pick up manufacture specific codes though, just obd2