My van is a 96 Grand Caravan with the 3.3l and about 202395 miles.

On occation, while stopped at a red light the engine will die.

Also on occation, while driving, the vehicle begins to feel very strange. It is like the engine is bogging down, but I barely loose speed and the tach also only drops slightly. Yet I am pulled against the seatbelt as if I was slowing down hard. The engine will sound deeper, and slower when this happens like it is pulling something heavy.

It occurs at completely random times and for random durations. I can interrupt it by either applying my foot to or removing my foot from the gas pedal. When I do this the vehicle normalizes until the next time. If I leave the pedal where it is it will recover on its own - in anywheres from a second to about 15 seconds.

It seems that it is more likely on warmer days. The sensation seems more pronounced when the AC is running.

This issue, whatever it is causes no codes, AT ALL.

I have driven around with different knowledgeable mechanics, and have been repeatedly told, "When it, whatever it is, breaks bring the van back and I'll fix it."

I would rather not wait until I am stranded on the side of some road before I find out what it is.

Any suggestions as to what could cause this kind of thing without producing a code?

 

2 guess would be a mass airflow sensor or a throttle position sensor.

 

Just because I do not know: The mass airflow sensor and throttle position sensor can fail without causeing codes to be set?

 

I had that happen in my 97, and was advised ehre to change my O2 sensors. I did, and it hasn't happened since. It did not set any codes either.

 

it can happen without setting a code. Is there a check engine light? I'm not sure what you are using to check codes but sometimes it requires 2 consecutive failures to cause a code which makes it a hard code and sets the engine light. Otherwise if it only happens once in a while there may be enough key cycles in between running the moniters to erase the soft code or pending code. The real way to find it is for a tech to capture the data while it is doing it. sorry

 

It can happen five times in one trip (apx 30 miles), or only once this month. No way of predicting it. However, even when it happens multiple times in one trip the engin light never comes on.

I have looked for stored codes using the key (on/off several times) and get 11/55 - I think. (Disconnected battery and End of Codes.)

I am also driving with a CarChip on the ODBII connector, these days. It also seems to record nothing unusual. For example, if I monitor the O2 there are fluctuations on accel/decel, but if I note the time of one or even two occurances of this event and look, on the computer, at the graphs in the CarChip software I see nothing out of the ordinary.

But definately no codes posted. If a code posts, no matter how brief, the car chip notes not only the code, but the date and time.

 

Cleaned Throttle Body - no change.

Performed "on vehicle" O2 sensor cleaning procedure - No change.

 

I know this thread is old, but have you changed your fuel filter? I had very similar symptoms with my '94 caravan and changing out the fuel filter solved the problem.

 

I think sciwan may have nailed it or has gotten very close. Gas filters are cheap enough to be worth changing just to see if that takes care of it. Otherwise I'd check for fuel pressure and even for a clogged fuel tank vent. Fuel starvation won't set a code (unless it results in a lean condition) but WILL give you all sorts of driveability issues.

 

drewc
Ck your battery connention, i have seen a loose neg cable cause lots of problems. Also when you clean the throttle, also remove and clean the AIS motor too. A bad AIS motor will also cause a stalling problem.