vibration when car stops

[clarksober]

Thanks a lot for all the comments.
I cannot see the engine speed as of newer car, otherwise I would know it's the limit of the car. I blame the throttle cable for it's not fully utilize the engine power when I found it's loose. The pictures says all, now I know the limit.
It was blocking the traffic while I was driving on the highway back MD, that's why I am wondering how fast can it be on your guys' car. my purpose of using this is not for highway, will drive it around 40, so it's ok since it can accelerate fast enough from 5-35 as petros mentioned.
I will check the spark plugs to make sure they all work and try the vacuum leak and turn up the idle speed a little to see how vibration changes.
Thank you all for the comments again, will let you know the result and newly emerging questions:)

[irowiki]

It was blocking the traffic while I was driving on the highway back MD, that's why I am wondering how fast can it be on your guys' car.

HA! Yes! Get used to people having to be patient behind you.


Yeah the auto really shines in city traffic. Keep us posted on your city MPG!

[clarksober]

update:
I spray the carburetor cleaner to those vacuum tubes connections, engine sounds normal-no change. I clockwise turned the idle speed adjust screw(upper one), no big change - It vibrated less if I press gas pedal a little bit.
Is it related to the air/oil mixture adjust? Is there anything I missed? I wanted to adjust the cable, but don't know where to adjust it since moving the screw left/right is not helping.
Need your guys' help, thanks.

[dlb]

did you read the FAQ? there are several other places and ways you need to check for more vacuum leaks.

there is no air/oil mixture. you must mean the air/fuel idle mixture. the screw to adjust this is plugged at the factory so it can only be adjusted it you carefully drill the plug out. it is located low down on the passenger side. if the plug is still in place, it is very unlikely it is the source of your problem. even if the plug is out, i would not adjust it until you have methodically worked through each of the other steps mentioned in the FAQ.

[Petros]

you should not need to mess with the idle mixture screw. If turning the idle speed screw (next to the throttle crank where the cable attaches to the throttle shaft) does nothing, just keep turning it inward until you can hear a speed increase in the idle (do with the engine idling). someone may have backed it out so it is not against the stop. If the idle speed is too low it will act like you describe.

when it is cold, is the idle speed high, and than drops down as it warms up? If so, that is normal operation of cold fast idle. It should come off the fast idle after warmed up and be up against the main idle speed screw stop. If the screw is backed off too far it will idle too low and hesitate from a start and likely idle rough and unsteady.

There are a lot of other thing to check too, but this one is simple and easy to adjust, and you will not harm anything by having it idle a bit high.

[clarksober]

Thanks. I won't mess up the idle/air mixture screw now.
I only adjust the idle speed screw, not the fast idle screw, because it has to plug the tubes first. Was it the reason why it didn't change the engine idle speed? cold start is fine, and it idles better when it's not in gear. Don't know what to change now. I will read the FAQ to try more.

[irowiki]

Keep screwing the idle in until the engine speed changes, as Petros said, it might be all the way out.

[Petros]

I am not sure what you mean by "because it has to plug the tubes first". What are you referring to? what tubes? do you mean you might have a leak in the vacuum lines? if so, yes, if there is a vac leak changing the idle speed screw will not likely make much difference. If you have a vacuum leak you have to find and fix it or no matter what else you do will it will not run properly so you have to make sure there is no vacuum leak before you can try to fix anything else.

I presume you have an automatic transmission by your posts, if so when in neutral there is no load on the engine and it will idle faster. When you put it in gear it engages the transmission and loads the engine down. it if slows it down too much it will idle unsteady and occasionally stall out, and hesitate starting from a stop. It will also act this way if it has a vacuum leak (which could be coming from a loose or damaged vacuum line, or from a leaky gasket or vac operated component). I suspect the "vibration" is a rough and unsteady idle when it is in gear, slowing the engine down, because when the trans is in gear the engine slows down too much.

[Swedeguy]

I’m having this same vibration issue and am curious what the resolution was. I know, old thread.

[dlb]

I’m having this same vibration issue and am curious what the resolution was. I know, old thread.

Looking back on this thread, I agree that motor mounts are the most likely cause of a vibration at idle. Have you checked yours?

[Swedeguy]

I have replaced them, and they are in good shape. I had checked all the other things that may cause that vibration, ignition system, carburetor, vacuum leaks, etc. all were good. It has always run a little on the hot side, and blew a little more white smoke than I thought it should, so I checked the coolant for CO2, and sure enough, blown head gasket. Currently using the Petros method for that replacement and during disassembly found some loose intake and exhaust manifold bolts, so may have had a vacuum leak too.

[Nordical25]

My BEA had also a rough idle, which resulted into higher vibrations. At least one reason was a leaky TVSV. Afterwards I needed to adjust my timing and it became already a lot smoother.

Therefore many minor things can affect your idle. You can spray start spray to intake manifold components if you suspect an intake leak for example.