My friend owns a Caravan that sputters or dies "on hard braking or when going fast in reverse" he maintains the van well, and I'd like to buy it, but not with this issue. I thought some wiring may be loose, but after tugging on all the looms around the engine bay, all were tight and the van idled casually. Braking hard and going in reverse fast both would cause a potentially loose component to have a forward inertia, and that's why I thought something could be loose. It straightened out after about 10-20 seconds. Any clues? It seems to idle and accelerate really well, so I'm not sure it would have to do with a lack of tune-up. Thanks

 

is the check engine light on or flashing?

 

Does it use an electronic throttle body or does it have a cable from the gas pedal? If it’s a cable and one or more of the motor mounts is worn, the engine could be rocking and the cable could be causing the throttle plate to close depending on how it’s routed.

Will braking in park/neutral cause it to stall?

 

It is on, not flashing. Not missing hard, idling well. ESP BAS light and TC light are on. Maybe another, I don't recall. Nothing to make it want to die though. He never got the light checked. 😑

 

I think it is electronic. I will have to check that. It definitely has to do with inertia because the engine doesn't falter in park. You can smash the brake all you want and it's fine. It only dies or tries to die when changing motion (hard braking, fast reverse.)

 

While you or someone else watches the engine, set the parking brake, put the van in gear (still holding the brake pedal) and rev the engine (brake stand). Look for the engine/trans assembly to rock excessively (excessive is the key here - it will move but you’re looking for one side to move more than the other).

Depending on the power train codes that are set, traction/stability control and related systems will be disabled. If you haven’t checked the codes, start there.