My 1994 Chrysler T&C van, 3.8L AWD auto, has developed a nagging problem. Intermittantly, under low load at around 60mph when well heated up, it will give a series of very fast lurches/hitches. This is about as fast as you say "jerk, jerk, jerk" in normal speech. The digital tach jumps from around 2000rpm to over 4000 each time but it is just a flash for each jerk.
I can now make this happen pretty regularly at the same spot on the highway. After 10-15 miles of driving to warm up, I go up a long, cross-over off-ramp at about 45mph. The other side slopes downhill. At the bottom, I am going 50 to 55 mph and the grade changes to uphill. I add a little throttle just to maintain speed and, "jerk, jerk, jerk". Having sped up, it goes away. I find it weird. I am worried it will strand me in a difficult situation.
I did a tune up with plugs, wires and oxygen sensor, no difference. A trans shop and a Chrysler dealer both looked at the tranny as I thought it might be dropping in and out of lockup but they found nothing odd. There are no recorded error codes according to them.
Any help/ideas would be greatly appreciated.
Donn F.