I’ve got a manual 1992 Jeep Wrangler (4.0 engine). It does this weird thing where it hesitates when you step on the gas (I always say that it feels just like my parents’ old riding lawnmower feels right before it runs out of gas). It seems to be related to moisture-- it happens mostly when it’s raining or really humid out. We’ve changed the spark plugs and distributor cap and had a mechanic change the fuel filter and a fuel line that had dry-rotted. But nothing has seemed to help. Any ideas??
How about the spark plug wires? Those are the classic signs of old, failing wires.
I agree with NYBo.
Other possibilities are a cracked coil housing or cracked insulation in the coil primary wire. One way to diagnose is to run the vehicle, spray water with a spray bottle and see if that affects the performance manually activating the accelerator linkage.