Purchased an 01 caravan sport with the braun lowered floor handicap conversion. 131k on the clock. Threw p0455, replaced gas cap, code cleared. Drove it a few times, threw code p0135, replaced upstream o2 sensor, code cleared. The handicap conversion does add a bit of weight, but the van seems sluggish. Idles good right at 800rpm. Has a smaller aft axle gas tank, but seems gas mileage is quite low. Cylinder 5 spark plug wires is sparking from wire to exhaust manifold, so i will be doing plugs and wires. Issue of concern... bringing the boy home from the hospital, going uphill about 40mph, the van would 'miss' every three seconds or so. Noticeable power loss, with a 5 to 600 rpm drop. No mil. No code. Unloaded the kiddos and drove around the neighborhood, 'miss' occurs uphill at any speed 10 to 45 mph. Any suggestions where to start with no codes?

 

If you have a known issue with a spark plug wire arcing, that is your problem. The plug is not firing. I suggest you start with replacing the plugs and wires.

 

Started the van, good idle, horrible 'miss' when accelerating. Code p1389 for asd relay. Disconnected battery for a minute or so, restarted, no codes, running smooth. Wouldnt asd relay kill ignition? Am i looking at a dying pcm? I wouldnt think its a low battery issue, alternator and battery are new as of july.