1997 Voyager with 3.0 has mysterious rough idle/won't take gas problem. It comes and goes. So far, we've tried a new downstream O2 and a new MAP sensor, new wires, new coil, new plugs, new cap and rotor, and it has a new fuel pump and filter. There's no real rhyme or reason to it, it usually happens after it's been running about 20 minutes. You can hear a sound sort of like air rushing coming from under the battery area. When it happens, the vehicle runs extremely rough, and won't take gas unless I floor the pedal. Often, just turning off the engine and back on will clear it. Ideas?

I had exactly the same problem with a 98 plymouth voyager with a 2.4 liter engine. Once I replaced the upstream O2 sensor in the exhaust manifold the problem was resolved. The OBD never generated a diagnostic trouble code.

1997 Voyager with 3.0 has mysterious rough idle/won't take gas problem. It comes and goes. So far, we've tried a new downstream O2 and a new MAP sensor, new wires, new coil, new plugs, new cap and rotor, and it has a new fuel pump and filter. There's no real rhyme or reason to it, it usually happens after it's been running about 20 minutes. You can hear a sound sort of like air rushing coming from under the battery area. When it happens, the vehicle runs extremely rough, and won't take gas unless I floor the pedal. Often, just turning off the engine and back on will clear it. Ideas?
I have the 3.0 and find that it is suseptible to gas that has any kind of water in it , it has the same type symptoms though it doesn't happen very often, as soon as I dump a bottle of water remover in it straightens out , might want to try a different gas station for awhile.

Check your voltage with a multi tester at the battery. See if it charging at the correct voltage for your make/model/year - especially if you can catch it while it is malfunctioning.

Another test would be to leave the car idling (when it is running smoothly) and turn on everything electrical you've got. Even hi-beams and 4-way flashers. Let it idle like that for 15-30 minutes monitoring the voltage. See if the overall voltage on the tester drops over time - if it does my guess would be a bad alternator.

Something else to check, if all that other stuff doesn't work:

I have a '93 Grand Voyager, and I had a sort of similar problem, a rough idle and very strong hesitance when I depressed the gas pedal. It also died while idling a couple times. I found that the problem was that a wire under the hood, between the engine block and the vehicle body, had been damaged by heat or whatever. My solution was slightly unconventional, I just took a wire with aligator clips on its ends and bridged the break in the wire, and that fixed it. I'm not sure what the wire was for (ideas?). Another symptom is that when I did drive it in that condition, the computer display (dont know if you have one) registered a much lower realtime fuel economy than I normally get.

My solution was slightly unconventional, I just took a wire with aligator clips on its ends and bridged the break in the wire, and that fixed it.

That didn't fix it, that's dangerous. One of these mornings you'll come out to start your van and it will be burned to the ground. I really think you should repair the wire properly, especially since you don't know what it does...

Something else to check, if all that other stuff doesn't work: I have a '93 Grand Voyager, and I had a sort of similar problem, a rough idle and very strong hesitance when I depressed the gas pedal. It also died while idling a couple times. I found that the problem was that a wire under the hood, between the engine block and the vehicle body, had been damaged by heat or whatever. My solution was slightly unconventional, I just took a wire with aligator clips on its ends and bridged the break in the wire, and that fixed it. I'm not sure what the wire was for (ideas?). Another symptom is that when I did drive it in that condition, the computer display (dont know if you have one) registered a much lower realtime fuel economy than I normally get.Your solution is VERY unconventional. That wire (in some cases a braided strap) serves a primary purpose and that is to provide a reliable ground plane for the engine block. Since many things bolted to the block require electricity to properly initialize and operate (fuel injection system, for example) it is *essential* that the engine block be properly grounded at all times.

Back in the good ol' days, engines were mounted differently. There were multiple devices and mounting points that grounded the block to the chassis (like the starter) and the only things going on in the electrical department of the engine were spark plugs, starter (of course) and maybe an electric automatic choke for the carb. It's WAY more complicated today.

In a perfect world, gasoline fumes are never present in the engine compartment. Unfortunately, this isn't a perfect world. If you don't find your vehicle in ashes one fine morning, it could explode when you twist the key - and it's far more likely to happen if it's parked in a garage out of the wind where dangerous gas fumes can be dissipated.

Your work-around has presented an opportunity for a spark (read "explosion") to occur. You should replace that grounding wire or braided strap IMMEDIATELY!