I haven't followed this entire thread, but the idle rising up and down
reminded me a problem I experienced when a vacuum hose had come loose.
 Have you checked your vacuum hoses to be sure they are all in place,
and none are split or cracked?  A vacuum leak could cause the idle
issue, but I never experienced the bucking.

Travis

On Thu, Nov 10, 2011 at 8:55 AM, jes poynter
<clementineintwilight@gmail.com> wrote:
> me again... a couple points i forgot to throw in there:
>
> someone mentioned we could bang on the catalytic converter to see if that
> would unplug something... is this a good idea?
>
> also, we aren't seeing the black smoke even though there is still the
> bucking/lurching thing. �i do believe we are still getting rather poor gas
> mileage though. �just more info to add to the diagnosis, please.
>
> thanks again! �jes
>
> On Thu, Nov 10, 2011 at 8:37 AM, jes poynter <clementineintwilight@gmail.com
>> wrote:
>
>> and good morning from san carlos, sonora!
>>
>> it's only a 2 hour drive or so from hermosillo but we made it.
>>
>> after changing the fuel filter, the type of gas, the temp sensors,
>> cleaning the grounds, checking the coolant system for any air/making sure
>> there was adequate coolant and reconnecting the O2 sensor we took it out on
>> the road.
>>
>> it seemed to be running amazingly, no lurching/bucking any of that as we
>> drove out of town. �the only things was the temp arrow on the dash
>> continuing to rise. �the blinking light ceased for a little while. �we're
>> thinking it's because the fan does not seem to be working.
>>
>> but then as we were on the highway and started going faster, the bucking
>> started again. �i tried cycling the ignition and it didn't help at all.
>> also, while driving the idle would go a little nuts as in down and then
>> back up, which i think may have something to do with the throttle switch or
>> air idle valve (?). �it seemed worse at certain times and then better.
>> actually as we went pretty fast, it stopped for a bit and then returned.
>> as did the blinking temp light.
>>
>> i have some tips on how to check/fix the fan as well as adjusting the
>> throttle switch, i believe. �i've also noticed a very slow drip of oil :(
>>
>> so folks, as i continue in my own research, if anyone is willing to
>> elaborate more specifically on the fan and the throttle or any other ideas
>> that come to mind, i'm open!
>>
>> i'm also wanting to continue our search for other vw owners around here so
>> i'll do that as we find a delicious lunch in a few hours. �but, tell me, if
>> we keep driving this way, what kind of damage am i doing? �in particular,
>> what's up with the oil dripping?
>>
>> as always, my gratitude for your knowledge and efforts grows. �thank you
>> so much for the help.
>>
>> jes
>>
>>
>> On Wed, Nov 9, 2011 at 11:36 AM, jes poynter <
>> clementineintwilight@gmail.com> wrote:
>>
>>> good morning again all,
>>> � � �so here's the scoop with our situation:
>>>
>>> i have replaced the fuel filter and now am using the premium gas here in
>>> mexico, as recommended by a few of you as well as a few people here.
>>>
>>> we are cleaning all the grounds, only that one important one under the
>>> a/c compressor that is the most difficult to reach. �i just got an extender
>>> to do so.
>>>
>>> i have replaced both temperature sensors.
>>>
>>> now what's happening is the gas/bucking thing seems to be mellowing out.
>>> yet the temperature light on the dash is blinking and the arrow is going
>>> all the way up. �my concern is that the temp sensor II i got here is
>>> actually for the other temp sensor... they aren't the same part, correct?
>>> in our van, the temp sensor II (the one on the left of the thermostat
>>> housing) is a square plug and the other (the one behind the thermostat
>>> housing if one is standing from the back looking at the motor) is a
>>> circular plug. �can someone please confirm that they are two different
>>> parts and that i may have the incorrect one for the temp sensor II? �or
>>> confirm that they are essentially the same thing and what else may be being
>>> triggered, insofar as why the temp light is blinking and why the arrow is
>>> shooting sky high?
>>>
>>> another thing i'm noticing is that i am not hearing the fan working any
>>> longer. �i noticed this a couple of days ago. �sorry to have not mentioned
>>> it until now. �i feel like it stopped after another mechanic looked at the
>>> radiator. �can i get some steps to fixing that also please?
>>>
>>> next, the idle is still a bit nuts. �i'm going to try disconnecting the
>>> air idle valve but am still trying to figure out how to adjust the timing.
>>> seems like an easy thing but i'm feeling a bit overwhelmed as i've
>>> mentioned.
>>>
>>> finally, should i go ahead and reconnect the oxygen sensor since we're
>>> pretty sure it wasn't acting up?
>>>
>>> i'll be looking all this up too on my own, via the bentley and the
>>> internet. �but i'm reaching out just the same. �thanks so much for all the
>>> help! �we're hoping to go south at least a little today ? :)
>>>
>>> On Tue, Nov 8, 2011 at 6:57 AM, jes poynter <
>>> clementineintwilight@gmail.com> wrote:
>>>
>>>> good morning all,
>>>>
>>>> � � �have been given some good suggestions about our problem(s) and
>>>> although i am concerned about having explained the issues corrrectly, it
>>>> seem that we've been able to rule out some things.
>>>>
>>>> � � �we disconnected the oxygen sensor, which was the most common
>>>> suggestion, and the problem still occurs. �so we're going with that it
>>>> probably is not that.
>>>>
>>>> � � �it's been suggested, more than once to replace the temp sensor II
>>>> which, if my research is correct is not the coolant tem sensor but a
>>>> cylinder temp sensor. �if any one is willing to elaborate more on this, for
>>>> example how i can determine which one we would need (i believe it is either
>>>> a square or a round one) it would be appreciated.
>>>>
>>>> � � �i feel as though i've checked all the hoses and everything seems to
>>>> be connected fine. �i'm going to be cleaning the grounds this morning as i
>>>> had to get some supplies for that task.
>>>>
>>>> � � �a couple of things i've noticed to add to the concerns are that
>>>> when we start it up now, the idle is way high. �and just sitting, it goes
>>>> all crazy jerky up and down. �another thing, we had cleaned out the AMF and
>>>> found a little oil. �it was mentioned that a little oil in the intake was
>>>> normal and nothing to be concerned about... then when i was underneath the
>>>> engine, there is what seems to be fresh oil on the bottom. �perhaps i am
>>>> just really naive and this is the way the engine is, with little bits of
>>>> oil covering and seeping out. �maybe it's just dirty from all the gas being
>>>> burned out. �at least it's not a big leak, right? �but i though i'd throw
>>>> it out there at least to have my concerns dismissed.
>>>>
>>>> � � �i'm feeling a little overwhelmed, as if there are so many things to
>>>> check and so many issues appearing. �so i am mostly writing to inquire
>>>> about the damage we may do should we continue to drive in this state.
>>>> we've been in one place for 2 weeks and things aren't really changing.
>>>> we'd like to get back on the road and attempt to continue to resolve the
>>>> issues and better the engine in general as we go. �is this a bad move? �i
>>>> certainly don't want to do more damage.
>>>>
>>>> � � �thanks for everyone's time and efforts, they are very much
>>>> appreciated. �i'll look forward to further education from all of you. �be
>>>> well. �jes
>>>>
>>>>
>>>> On Sun, Nov 6, 2011 at 12:22 PM, jes poynter <
>>>> clementineintwilight@gmail.com> wrote:
>>>>
>>>>> hello all,
>>>>>
>>>>> � � �this is my first email and i am new not only to the community but
>>>>> also to working on my vw :) �i will do my best to be accurate and
>>>>> informed.
>>>>>
>>>>> � � �we have been having issues with a lot of black smoke/gas burning
>>>>> as well as the hesitating and bucking that seems to be so common with the
>>>>> vanagons. �we have had the fuel injectors cleaned, the coolant system
>>>>> checked out and have replaced the AMF most recently with the problem still
>>>>> occurring. �we have had a friend here in the community send out our problem
>>>>> to you all yesterday and received the suggestions he was given regarding
>>>>> disconnecting the oxygen sensor and also cleaning the ground on the left
>>>>> cylinder head, both the connections and where it goes onto, as well as
>>>>> cleaning the distributor cap.
>>>>>
>>>>> � � �i do apologize but i need to ask for your patience and expertise
>>>>> here. �i am more than willing to learn how to work on this myself and do
>>>>> have a copy of our manual. �however i am writing for guidance and
>>>>> elaboration on the above suggestions.
>>>>>
>>>>> � � �in regards to the 1st suggestion of disconnecting the oxygen
>>>>> sensor, we did so at the connector and the problem seemed to persist during
>>>>> a test drive. �i read elsewhere "Disconnect the Oxygen sensor wire and see
>>>>> if that does not correct the condition. It is the green wire on the extreme
>>>>> left side of the engine compartment." �and am wondering if this is a good
>>>>> next step. �so i went out to take a look and am just not sure which one is
>>>>> the correct wire. �additionally, there seems to be one wire already
>>>>> disconnected, though it is a green and yellow/white wire with a yellow
>>>>> rectangular blade terminal (i think) at the disconnected end. is this
>>>>> supposed to be disconnected? �is this the wire to the oxygen sensor already
>>>>> disconnected? �if not, what is it and do i let it be?
>>>>>
>>>>> � � �in regards to the 2nd suggestion, the easy part of cleaning the
>>>>> distributor cap i checked up on and it is very clean. �the portion i am
>>>>> having more difficulty with is knowing exactly where to go to clean the
>>>>> ground on the left cylinder head. �i honestly don't know where it is. �i
>>>>> apologize but am genuinely asking to learn from anyone willing to teach me
>>>>> here in the community. �a picture or a place in the manual to look for the
>>>>> picture would be very helpful to me as reference. �and again my gratitude
>>>>> for your patience.
>>>>>
>>>>> � � �i realize i can continue to look up pictures of these parts and
>>>>> glean info that way, which i will do, but i am reaching out as i have been
>>>>> dealing with this issue intensely for almost 2 weeks, working with other
>>>>> mechanics and not getting very far, literally as i am traveling with my
>>>>> family in m�xico but we haven't driven anywhere in days.
>>>>>
>>>>> � � �additionally, i should mention, i have been learning about the
>>>>> "vanagon syndrome" and researching the fix with the capacitor/transformer
>>>>> part and do see the options available there; i just don't want to have to
>>>>> wait on a part another week if there are options to check. �i want to at
>>>>> least be active in attempting to understand the issue and learning about
>>>>> the engine. �i have been reminded that i can learn to fix these issues
>>>>> myself with the help of those who know and are willing, as well as my own
>>>>> motivation. �if there are any other specific questions i can answer for
>>>>> anyone who is interested in helping me resolve this, i'll gladly do so, of
>>>>> course. �and i think it should be stated that any other suggestions are
>>>>> most welcome.
>>>>>
>>>>> � � �thanks! � jes
>>>>
>>>>
>>>>
>>>
>>
>