1997 Grand Caravan w/3.8 - stalls at 40mph and below, jerks/stumbles at highway speeds

97 Grand Caravan with 3.8, front wheel drive. This intermittent problem is
driving me nuts. At speeds around 35mph or so the van will stall. At
highway speeds, 60, 65 it will buck or stumble or jerk once, but not stall.
It's like if the transmission disengaged then re-engaged. Also at highway
speed when it does this the speedo jumps up to around 80mph. And it will
knock it out of cruise control if it's on.

There are no trouble codes after this happens. And it does not happen all
the time. Once a day if that much.

Any clues?

Thanks,
sdm

 

I'd start with output sensor on trans. Sounds like it's going flaky. You may
have another issue too, but this is a good start.
Larry

 

I assume you are talking about the ouput Vehicle Speed Sensor. Does the
input Vehicle Speed Sensor have any influence on the speedometer?

 

Could be a missfire, Normally the speed sensors will set a fault and turn
the lite on, maybe have the dealer/ garage connect the scan tool up and test
drive it to see what is going on.

Try spraying the egine with water and test driving it, maybe a plug wire
arcing?

Glenn Beasley
Chrysler Tech

 

My 3.3 acts like that when the injectors get dirty, or I have a bad batch of
fuel. You could try adding some fuel system cleaner/injector cleaner.
(Remember injector cleaner needs a few trips to work its magic)

 

Humm, would one cylinder missfire stall the engine? In fact I did have a
bad plug wire a couple of years ago. It just caused a stumbling on
accelleration.

The thing that bugs me, on the highway it bucked real hard, the speedo ran
up around 80+mph, then all was fine. No codes set. I've been driving this
van for a week now trying to get it to do what it does. So far it's only
bucked at highway speeds once an stalled pulling into a parking spot once.
That should give you some idea how intermittent this is. And never any
codes set. I do have a scan tool, but it only reads generic OBDII codes.

I'm trying to avoid the dealer at all costs. I know what they will say... I
need brakes and a new muffler... (which I don't)... LOL

Something else I'm remembering. It's done this for a while now, again
intermittent and not so much after a good warmup. It seems that when
comming off part open throttle and slowing down to a stop, the tranyy does
not want to downshift. You can feel it bump/jerk when you do finally come
to a complete stop. As if the lockup torq converter just won't let go or
something. Would an bad VSS have an influence on this behavior?

What would happen if the lockup converter let go momentarilly on the
highway?

 

Im with you avoid them at all cost. They may have a better chance at fixing
it, especially if they have to go inot the CVI's to see what the trans is
doing