97 Grand Caravan Stalling - no codes set

I have a 97 Grand Caravan w/3.8 front wheel drive, @130,000+ miles.

It stalls at slow speed. Probably anywhere from 5 to 20 miles an hour, foot
off the gas usually. No trouble codes are ever set. It starts right back
up with no problem. I changed the output-VSS hoping that was the culprit
after reading other posts suggesting that would be a place to start... no
help.

At high speed it will buck hard once and then be fine. It does not stall at
highway speeds, just bucks once.

The problem is intermittent. It sounds like a sensor to me, but there are
never any codes set. I really don't want to take it to a dealer. I know
what will happen. They will charge me $100 plus to look at it and then tell
me they can not duplicate problem.

What would cause the van to just stall and not set any type of code?

Any clues?

Thanks,
sdm

 

Give a bit more info please like when the spark plugs, ignition wires, air
filter, PCV were last replaced. When was the throttle body last cleaned
properly? How does it idle when the engine is warm and stopped at a traffic
light? Any noticeable decrease in fuel economy? Does it behave differently
when the engine is hot or cold? Any other symptoms at all?

Given there are no engine diagnostic codes being set, I'd first suspect the
basics. At going on 9 years and 130K miles, your maintenance history is
very important before venturing a guess at where to look based on just the
symptoms you described. Sounds like it needs the plugs, wires and filters
(air and gas) replaced as a starting point if they have not been done
recently. I'd also definitely clean the throttle body real well too. You
may also want to try a good fuel injector cleaner in the tank as well while
you are at it.

Bob

 

It needs the throttle body cleaned. Have it removed and disassembled cleaned
thoroughly and reinstalled with a new gasket. Reset the AIS and you're good
to go.
Larry

 

Throttle body and injector system service at dealer 34,523 (so they say,
not convinced they really did the work, no marks or clean spots near or on
throttle body at the time)
PCV 66,130
Plugs and wires 100,957
Fuel filter 101,202
EGR valve and control 101,340
Leak Detector Pump 116,660
Trans filter and fluid 131,578
VSS-output 131,970
Air filter recently checked, clean
Oil and filter changes done regularly

Maintenance pretty much followed according to schedule as recommended by the
maintenance book that came from Dodge.

Other than the intermittent stalling as slow speed and buck at high speed,
the van runs great. Idle is as smooth as it always has been. Fuel economy
is good, no noticeable drop from earlier years. Hot or cold van seems to
run the same.

The only other thing I can think of, the trans was getting a little
noticeable while shifting. Particularly when coming to a stop. You can
feel a nudge or bump as it downshift coming to a complete stop. As if at
the last second it decides to shift into 1st gear.

Any recommendations on a fuel injector cleaner?

 

What is the AIS?

 

Air Intake Servo (I think this is right)... It controls the air mixture to
the Throttle Body. Based on your nice listing of the service history
(thanks), and assuming it idles a bit rough, I would start at the TB and do
as was suggested by jdoe with disassembling and cleaning the TB and the AIS.
Make sure you use a new gasket when you reassemble. In addition, if it was
me, I'd toss a large bottle of Techron fuel injector cleaner into a full
tank as well. If this does not help, I'd remove, inspect, and replace the
spark plugs next before looking further to make sure these are not fouled
and firing properly.

Good luck and let us know how you make out.

Bob

 

That sounds like a dirty throttle body starving for air as you close the
throttle blade, You don't have to remove it, just take a can of throttle
body cleaner and a tooth brush and clean the inside bore of the throttle
body and the top and bottom of the blade, Of course do this with the engine
off.
The Bucking problem would be something else and not related to a dirty
throttle body.
Glenn Beasley
Chrysler Tech

 

Automatic Idle Speed motor. Stepper motor moves a pintle in and out in a
bypass circuit around the throttle plate. Notorious for gumming up in MPI
FI engines as there is no constant supply of fuel to wash it clean. If
your PCV valve gums up the engine oil mist cloud is routed downstream of the
throttle plate and gets sucked in to the air cleaner (what was once the PCV
intake is now the exhaust) and soaks the intake system with fine oil mist
over time. IF the AIS pintle gets gummed up it becomes sluggish and cant
open up quickly enough when you remove your foot from the accelerator. In
any case a good cleaning with a tooth brush and some O2 sensor save solvents
(brake cleaner is ok if non flam ie Gunk AM720 in green can). Run engine
and blip the throttle and when the throttle closes squirt b/c into the
throttle opening and repeat many times.

 

Sounds good to me. Now, what would cause the buck at highway speed? I
believe the two are related.