88 Caravan 3.0 stumbles 10 seconds after coasting or stopping!

I have a 1988 Caravan 3.0 that has developed a problem where after you
stop for a 10 - 20 seconds at a light or if you coast, the engine
looses all power and all but stops. The engine may be running at 200
rpm if that and sometimes stalls. If you floor the accelerator it will
continue to stumble for 10-15 seconds then will snap your neck when it
recovers. Will run all day @ a constant speed of greater than 20 MPH
with good gas milage and acceleration. Just don't coast or idle the
engine! I have noticed that the fuel pump seems to labor when the van
acts up. The fuel pump and the filter have been replaced. I reset the
computer and have driven the car over 200 miles and the problem
persists. I received a code 12 and 15 from the computer. The van does
not have cruse control and I have been told the 15 is related to a
speed sensor that is for the cruse control. Any ideas?


Thank you,
Randy

AB9GO wrote:
> I have a 1988 Caravan 3.0 that has developed a problem where after you
> stop for a 10 - 20 seconds at a light or if you coast, the engine
> looses all power and all but stops. The engine may be running at 200
> rpm if that and sometimes stalls. If you floor the accelerator it will
> continue to stumble for 10-15 seconds then will snap your neck when it
> recovers. Will run all day @ a constant speed of greater than 20 MPH
> with good gas milage and acceleration. Just don't coast or idle the
> engine! I have noticed that the fuel pump seems to labor when the van
> acts up. The fuel pump and the filter have been replaced. I reset the
> computer and have driven the car over 200 miles and the problem
> persists. I received a code 12 and 15 from the computer. The van does
> not have cruse control and I have been told the 15 is related to a
> speed sensor that is for the cruse control. Any ideas?
>
>
> Thank you,
> Randy

Hi Randy...

15 = "No vehicle speed sensor detected during road load conditions"

Ken

"AB9GO" > wrote in message
oups.com...
> I have a 1988 Caravan 3.0 that has developed a problem where after you
> stop for a 10 - 20 seconds at a light or if you coast, the engine
> looses all power and all but stops. The engine may be running at 200
> rpm if that and sometimes stalls. If you floor the accelerator it will
> continue to stumble for 10-15 seconds then will snap your neck when it
> recovers. Will run all day @ a constant speed of greater than 20 MPH
> with good gas milage and acceleration. Just don't coast or idle the
> engine! I have noticed that the fuel pump seems to labor when the van
> acts up. The fuel pump and the filter have been replaced. I reset the
> computer and have driven the car over 200 miles and the problem
> persists. I received a code 12 and 15 from the computer. The van does
> not have cruse control and I have been told the 15 is related to a
> speed sensor that is for the cruse control. Any ideas?
>
>
> Thank you,
> Randy
>

Yes the speed sensor is for the cruise control but has other functions as
well. One thing it is used for is Idle. The speed sensor tells the Computer
that the car is coming to a slow stop and it will require the AIS Automatic
Idle Speed Motor to hold the engine RPM to prevent stalling.
Repair that problem and clean out the throttle body really good, then take
it from there to see if there are other problems.

Glenn Beasley
Chrysler Tech