Car is jerking when trying to keep steady mph

[daddyruiz]

While reading this please try to keep in mind that I am also still struggling with a bouncing idle.

When I'm trying to keep a steady 35 miles per hour or steady speed the car jerking motion. It's really bog down completely, it just jerks like its not getting gas or something, it kind of resembles letting off the gas and pressing it again quickly. As long as I'm accelerating it's fine and slowing down is fine also. Not sure what I should be looking for.

I do have a video, will be mainly for hearing it since rims don't fluctuate at all when it happens.

https://www.youtube.com/watch?v=YfUEB8t7PNY

[deevergote]

I've never seen anything like that before. Pull your spark plugs and see what they look like. I have a feeling there's something screwy in one cylinder. The plug will likely be fouled or burned, depending on what is happening. Something tells me either one plug isn't firing properly, or one injector isn't spraying properly. That's just a guess based on limited information, but it's a start. I expect the plug condition will tell us more.

[cp[mike]]

This type of symptom tends to point me toward the ignition system.

The igniter unit inside the distributor has a tendency to start to go bad where only at higher RPMs, it starts to skip and miss a couple of the firings, giving that engine stutter. I actually suspect that it is happening to your car all the time, you just don't notice during acceleration or deceleration.

If you can get access to a replacement, I would try a new igniter unit, if I were in your shoes. Paired with inspecting and possibly replacing any other components of the ignition system that are getting old or crudded up, like the spark plugs, or distributor cap/rotor. Like deevergote said above, this will also help you determine other factors at play: perhaps you will find one of the spark plugs is damaged, or that the distributor contacts are corroded, or perhaps that the ends of your plug wires are covered in oil...

The reason ignition and injectors are suggested as possible culprits is because the "miss" you are feeling appears to only be affecting a single cylinder at a time. If the fuel pump itself died, whole sections of time would go by where NONE of the cylinders could fire - this seems to be inconsistent where only occasionally, one of the firings gets skipped, but the rest continue on their way. What could cause a single cylinder to skip firing? If it was a bad compression leak, it would be pretty much just not firing at all - your cylinders seem to be working fine one moment, not for second, then working fine again. repeat. This says it has to be a component that deals with individual cylinders: spark plugs, fuel injectors, distributor wiring.

on that note, inspect your engine wiring harness for damage. Perhaps let the car sit and idle, and push on some of the wiring by hand to move it around - see if you can find an area that causes the car to die out. Perhaps your wiring is only losing contact when the engine is vibrating or moving a certain way.

[daddyruiz]

Tat was my thought also. It's been doing that lately, so I already pulled my plugs and cleaned them. Granite, they could use being replaced which I will do this week. I have a pic of how they looked when I pulled them, but unfortunately no option to upload it. Says I cannot post attachments.

[daddyruiz]

cp[mike]

I did notice the distributor cap contacts are a little corroded, the plugs could use some replacing, and well the plugs are also covered in oil. But not all, just the number 3 plug had a good amount of oil on it.

[Fleetw00d]

cp[mike]

I did notice the distributor cap contacts are a little corroded, the plugs could use some replacing, and well the plugs are also covered in oil. But not all, just the number 3 plug had a good amount of oil on it.

Oil on the electrode end or on top where the plug wire attaches? If on the electrodes, then you have oil leaking into the cylinder (valve seals or rings). If on top, then the tube plug seals need to be done. If there was a lot of oil on top, than can affect how well the plug fires.

[mjsstanley]

I've had 2 CBs do this and it turned out to be the o2 sensor. Could would start to jerk, I would come to a complete stop and then the CEL would come on. Cars drove fine with the CEL on. Just another possibility. Wouldn't hurt to have a new o2 sensor if it hasn't been changed recently.

[deevergote]

I've had stuttering issues due to the o2 sensor before, but never experienced anything like in the video. Not saying it couldn't do that, but my failing o2 sensor usually just resulted in horribly sluggish acceleration for a few seconds (randomly), followed by full power. Once the CEL popped on, it worked just fine.

daddyruiz, an easy way to test this is to simply unplug the o2 sensor. Tie the wire back so it doesn't get damaged. It'll turn the CEL on once the car warms up. If the problem never happens again, then the o2 sensor may be your culprit. It's free and relatively easy to check this, so it couldn't hurt! If you do end up replacing the o2 sensor, get Denso or NTK only. NO BOSCH! They don't work. No other brands besides Denso and NTK are guaranteed to work, so stick to one of those. RockAuto.com usually has one or the other for about $35. Be sure to get the proper sensor for your particular year and trim level (the sensor location and plug will vary depending on those things.)

[masospaghetti]

Have you tested fuel pressure? Low pressure will cause a lean condition and a bucking sensation.

[h22sparkle]

When I had my cb both and most of the time it turned out to be my ignition system. Mainly the coil or the distributor just before it went bye,bye. You can mostly check that if you notice any orange dust in the inside once you take the cap off.

Once you see alot of that be prepared. Never had a problem with the o2 sensor too but I think it would be in your best interest to to keep an eye out for that cat converter lol if you still have it on the car.

[daddyruiz]

Thanks for the reply everyone. Guessing O2 sensor will be getting checked today. I got all new plugs, wires, distributor cap, went ahead and did the valve cover gasket and all the seals, still doing the same thing. I read somewhere about possibly being the EGR passageway. How likely do u guys think that is?

[GTRON]

I've had stuttering issues due to the o2 sensor before, but never experienced anything like in the video. Not saying it couldn't do that, but my failing o2 sensor usually just resulted in horribly sluggish acceleration for a few seconds (randomly), followed by full power. Once the CEL popped on, it worked just fine.

daddyruiz, an easy way to test this is to simply unplug the o2 sensor. Tie the wire back so it doesn't get damaged. It'll turn the CEL on once the car warms up. If the problem never happens again, then the o2 sensor may be your culprit. It's free and relatively easy to check this, so it couldn't hurt! If you do end up replacing the o2 sensor, get Denso or NTK only. NO BOSCH! They don't work. No other brands besides Denso and NTK are guaranteed to work, so stick to one of those. RockAuto.com usually has one or the other for about $35. Be sure to get the proper sensor for your particular year and trim level (the sensor location and plug will vary depending on those things.)

You can buy a NTK for $15 on amazon

[deevergote]

Wow, seriously? I remember the days where o2 sensors were like $80!

[Bolex]

I have similar issue except my cb is bouncing when I drive slow in third or fourth speed.

[daddyruiz]

Well...I unplugged the O2 sensor. I got the check engine light but car still did the same thing. Car was at operating temp when I tried it also. Another thing I did was unplug the EGR valve and it still did the same. Should I plug the vacuum hose from the EGR and them stem with it unplugged to check it properly?