Bucking while driving
 

When I'm driving my car, it will suddenly start jerking pretty hard about every second then all of a sudden it stops. I then engine has little power when this happens, and it can happen in every gear.

This happened while on the interstate, and I had a chance to do some troubleshooting. I put the car in neutral and the jerking stopped. I hit the gas in neutral, and the engine sounded fine. When I put the car back into 5th gear, the jerking started again. I slowed down, and 4th gear had the same problem. When I hit the gas in gear, the car tried to accelerate, but the jerking was working against me. My engine had very little power. I ruled out bad gas, because I ran the car to close to empty and got gas from another station.

My idle was oscillating all of the time, so I thought that this might be causing the problem. My fast idle valve was the problem. It was open when the engine was hot, so essentally it created a vacuum leak. I replaced it, and now my idle is fine. I had to reset my ecu, becasue after installation, my idle was stuck at 3000 rpm.

I still have the bucking problem intermittently, but have observed some more information about it.

It usually happens from ~ 2000 through 3000 rpms. The engine loses most of its power while it bucks and have to push through 3000 rpm to get it to stop.

It happens bad when the coolant temperature is rising from cold to normal operating temperature.

I think that I can feel the problem all of the time from 2000-3000 rpm, but it is definitely worse when the engine is warming up. The bucking can still be bad when the car is warmed up though.

Any suggestions/advice would be greatly appreciated.

RE: Bucking while driving
 

have you checked all the secondary system ?? plugs, wires, cap, rotor ???,,,,,,,,,chk engine lite on ?? any codes stored ??

RE: Bucking while driving
 

When this started, I replaced rotor cap and plugs. Wires have correct resistance, and I sprayed water over them to check for arching.

Replaced coil and ignitor with old working parts.

No CEL and no codes stored.

This one has been tricky for me.

RE: Bucking while driving
 

auto or manual? edit: nevermind MT - Manual Trans

pull your plugs and see if they are OK

all the wires in the right spots?

check the ignition module it may be failing when it gets warmed up.

RE: Bucking while driving
 

All the wires are in the correct places.

I replaced the plugs several months before this started happening, but I will recheck after this winter storm passes.

I had an ignition control module from my old distributor (the old one had a crack in the housing) and swapped it out along with the old coil.

I still have the same problem.

I'll post when I look at the spark plugs.

RE: Bucking while driving
 

Couldnt be a bad motor mount could it? Since it works in neutral...idk though

RE: Bucking while driving
 

The front motor mount was replaced right after this started happening. I had just noticed that it was cracked and had a new one on the shelf waiting to intsall. The trans mount looks ok. I will find out about the side mount when I do my timing belt.

Now that leaves the rear mount. It is pretty hard to get a good look at it. I know that there are some vacuum tests to inspect it. Is there any tricks that you could pass on to identify a faulty rear mount?

It looks like a PIA to replace. Does the intake manifold have to come out to do this?

I don't want to throw a lot of parts at this problem without some sort of verification of a failing part. I was afraid that a dealership would most likely take this route.

Thanks

RE: Bucking while driving
 

what kind of plugs did you use ? make sure to use NGK ZFR5F-11

RE: Bucking while driving
 

i used NGK Irridium. Not sure about the number. Have Accords had problems with these?

RE: Bucking while driving
 

did problem start to happen before or after you replaced the plugs ??
any work you did just before problem started to happen ??
and i would use the plugs that it is called for NGK ZFR5F-11 ..

RE: Bucking while driving
 

The plugs were installed several months before the problem started happening, so the problem arose after the plugs were put in there.

I will buy the NGKs you mentioned. It will be a cheap test/fix to verify if the Irridium plugs are crap for Accords.

The only thing that I can remember doing before the problem started happening was trying to loosen the O2 sensor with no luck. I didn't try too hard, but used the special socket and briefly tried a 22mm wrench.

RE: Bucking while driving
 

there is no vacc at the rear motor mount , once the idle speed is over 700 rpm,,,(AT tranny ),,,,,,to chk for a bad motor mount, put a floor jack under the tranny and raise car up a bit, look at the mount if there is a crack or split in it ......

and to replace it 1 does not have to remove the manifold,, 1 can do it from under the car... if you cross that bridge i will tell you how to replace it

but that is not the problem you are experiencing anyways

RE: Bucking while driving
 

Im gonna throw this out there because no one else has, but could it possibly be clogged EGR ports?

RE: Bucking while driving
 

yes it could Poser,, a bad egr valve as well could do it

RE: Bucking while driving
 

Fuel filters?

Weak fuel pump?

RE: Bucking while driving
 

I cleaned out the egr ports about a year ago. They were pretty clogged. How long does it take for them to clog? I didn't clean out the EGR valve yet. Are there any precautions when doing this?

As for the fuel pressrue, I need to make an adapter that will fit into the fuel rail, unless someone knows where to buy the right adapter (its 12x1.25 right?)

RE: Bucking while driving
 

Well, I did a lot of work on my car over the holidays, and the bucking hasn't come back in over a month.

Sorry I haven't posted in a while regarding this thread. I hope this can help someone else with a similiar problem.

I am a graduate student, so I live in an apt. Over X-Mas at my parents house, I did a lot of work on my car (new timing belt, etc). The miss was still there after the timing belt change. After heating the O2 sensor for ~15 min with a torch, it came out immediately from the intermediate pipe. Replaced with an "OEM" NGK sensor that was mispriced at $50 on their website. I also found that the spark plug in cylinder 3 was corroded with white oxidized metal on the ground (bent) electrode (I suspected a lean fuel mixture from the list of causes). I replaced the fuel injectors with cheap used ones off of Ebay for $20. I am going to send the originals out soon to get flow tested and balanced. All the resistances were within spec for each fuel injector. The EGR ports on the manifold were still unobstructed.

The bucking is gone, so I am not sure if it was the O2 sensor or a plugged fuel injector. Since the timing belt job took me a while (my first time), I had to replace multiple components at one time. I will try to report back with the results of the fuel injectors. I can't wait until I gradutate, so I can troubleshoot one item at a time.

The fuel filter was replaced about a year ago, so I didn't suspect a problem with that.

Thanks for all of your help, I certainly appreciate it.
John

RE: Bucking while driving
 

had the same problem back in summer of 06, did everything you mentioned and it didn't make the problem any better. Turned out to be a bad fuel pump. Never thought it was, but, it took taking it to the Honda dealership to figure it out. Good luck!

RE: Bucking while driving
 

So far, the problem hasn't come back.

It always happened when the car would get close to normal operating temp, so either it was the O2 sensor not kicking in quickly or the fuel injectors leaking. When I get the flow tests back from the injectors, I'll have a better idea of what is going on.

RE: Bucking while driving
 

I'm very interested to see the final outcome of this because my car is doing the EXACT same thing. So far I've only replaced plug wires, plugs, fuel filter, distributor cap and rotor... I'm new to this, so when I went to check my injectors I stopped because I was afraid of spilling fuel all over. I was just going to disconnect them one by one to see if one of them is bad, but an overall cleaning would be a good idea I think anyway. I think I'll take the car in to the shop again this week and have them do a complete fuel system service, clean injectors and rail and test flow, all that stuff.

In any case, please let us know what happens!

RE: Bucking while driving
 

The problem hasn't come back.

I haven't sent off the injectors yet.

I still am leaning towards the O2 sensor, but that is based on other posts I read in several forums. My check engine light was never on and no codes were stored. I would make sure that your ECU doesn't have any codes stored.

RE: Bucking while driving
 

How has your car been? Ever test the injectors?

RE: Bucking while driving
 

could be the distibutor...had tha same problem once in a 95 altima it was the distributor..jumped and jerked alot then quit....pretty expensive though...

RE: Bucking while driving
 

I didn't send off the fuel injectors. I packed them in a box this morning and was going to send them off to get cleaned this week. After I replaced the O2 sensor, that bucking problem did not show up until last week. Recently, my car has been having problems that might be fuel related.

I have gotten a code 43 four times now since Christmas (either O2 sensor or fuel supply system). I had one pop up last night and it returned this morning while driving, so I cleaned the O2 sensor plug and put some dielectric greas in there. I wish the problem was there all of the time, so I could figure this one out.

I think that I might just order the honda fuel pressure gauge and test the fuel pressure at the rail while driving. This is really frustrating right now.