Vibration at idle (and a little above)

Do you really want this person working on your vehicle ?

1 Like

Do you have the proper springs and spacer bolts at the catalytic converter and front exhaust pipe connection to allow movement?


1 Like

Not anymore.

Maybe not? I don’t know could they be too tight? The first thing I noticed when I got the car back was the exhaust was much louder. The vibration was almost unbearable too. It did need new mounts which helped, but obviously didn’t help enough.
Quick story:
About a month after the I got the car back, I started hearing a rattling noise like empty cans in a bag from under the car. I told my brother in law about it and he fixed it. I don’t know exactly what he did, but he got under the car and told me a bolt was stripped. Maybe a hanger? I wish I knew more. The sound has been gone since.
I had been fixated on the engine and neglecting the fact that the cat had been replaced too.
How tight should the springs be? I may be able fix it myself if need be.

did he use something like this on your exhaust system. if he did not you will get a vibration through the whole chassis.

1 Like

Again, I don’t know. Would I be able to see it? Does that go between the cat and the pipe? I do have vibration through the whole chassis. You can feel the vibration from outside the car if you put your hand anywhere. The muffler tip is also shaking a little.

it goes on a bracket like this that is attached to your car. and the other hole in the bushing goes to your exhaust hanger on the exhaust system. your bushing and set up might look slightly different being I did not look for your specific vehicle, but the same principle. and yes you can see it by looking under your vehicle. there should be a few of them at different spots in the exhaust system. there purpose is to help stop vibration and give exhaust system a little play.

1 Like

sorry I forgot to put image. its there now.

1 Like

Good info, Thanks. I’ll take a look. What are the chances this could be related to the rebuild? How much of the exhaust do you have to remove to replace the cat?

https://www.gmpartsonline.net/v-2009-pontiac-vibe--awd--2-4l-l4-gas/exhaust-system--exhaust-components

Here are my spring bolts. Left side(facing the engine):


Right side(The nut that’s pointed out wasn’t there originally. My mechanic put one on there. I didn’t ask him to.):

One more thing. I don’t know if I mentioned this, but the car jerks/shakes (sometimes violently) when started.
Once I had all the mounts replaced, I could not tell the car had been started or even feel it running for about an hour until the vibration returned and I’ve been chasing that high ever since.
I think that covers my situation and symptoms.
Thanks again for all the input :slight_smile:

I’m probably of little help here but I keep going back to that oddball spark plug. It is just not right and looks pretty bad for only 10k miles. Generally at 10k they still look new unless there’s an issue. Considered throwing a new plug in that cylinder just for giggles to see if it will make a difference?

Going off into the woods here so this is possibly a stretch but I did run into an oddity on a 4 banger years ago with a spark plug that had developed an odd appearance. Do not remember the type of car as it’s been 15-20 years, etc.

There was an EGR glitch which prevented the EGR from fully closing. This bled exhaust gas into the intake all the time. Logic would dictate that this would affect every cylinder and not just one. However, the EGR port in the intake was closer to one cylinder than the others and this difference apparently made a difference in how that cylinder was performing compared to the others. EGR repair cured that one.

That could explain the plug, the vibrating vacuum gauge needle, and vibration. This is all theory (a.k.a. WAGing) at this point.

And there is also the weak valve spring theory. That can cause a funky gauge needle and rough idle. I installed a Chevy long block once that ran great but idled rough. After a bit of wrestling I found that one of the valve springs on the passenger side head was weak. So I aired the cylinder up, installed a new spring, and all was fine.
So much for “quality remanufactured long block…”.

Will still think about this. Hope it helps; or feel free to trash the whole post… :blush:

1 Like

I replaced the plugs about 5000 miles ago. It didn’t help much if at all. I’ll pull the newest ones and take a look. I’ll actually pay attention to which cylinder each one came from this time :slight_smile:

Plugs look good. The grounds are all white like the last ones, but no buildup whatsoever. One of the old ones was pretty loose, so maybe some oil ran down on it or something.

When pistons are replaced (rather than simply installing new rings) , that may require that a machine shop (who will have the necessary specialized equipment) do a procedure to properly balance the rotating assembly.

Misfires, engine/transmission mount problems, etc can cause this sort of thing too, but I presume you’ve already checked for that.

1 Like

I’m still not 100% on the mounts, but they are all fairly new and I don’t know what else to check. My OBD says no misfires basically ever and my plugs look great.
I watched a video of someone who did the piston replacement on a Toyota Camry (same engine) and it ran great, better than before, he said. He just did it in his garage with normal tools. Mine runs worse now, so something was screwed up during the rebuild. I’m fairly confident it’s the engine (not the exhaust) because the vibration is consistent and RPM specific. Load (stopped in gear, AC on, etc.) is irrelevant-the engine just vibrates/shakes now. That’s why I was leaning toward it being the balance shafts, because the vibration is worse than a 4 cylinder engine without balance shafts and significantly worse than my engine was before.

The engine mounts are easier to fiddle with than the balance shafts, so I’d start there. I’ve never been clear on the sequence of events with the mounts, but it would seem it’s time to support the engine, loosen the mounts (all of them), be sure you are keeping the engine in the right position, and then retightening them all. Not just one or two, all at the same time.

1 Like

You may be right. But, here’s something I may not have mentioned.
Before the rebuild, the engine was smooth throughout the rpm range, but vibrated a little when stopped in gear due to the mounts being worn (all 12 years old)
After the rebuild, the same mounts were re-installed, but the vibration was stunning. Before, I could put the car in neutral or park to smooth it out, but after, it didn’t make any difference. The car just shook unless I was moving over 10 mph. The engine and exhaust were noticably louder too. Replacing the mounts one by one made incremental improvements, but I’d like to figure out why the car was so rough after the rebuild as the root issue.