Why would my van keep misfiring after replacing plugs and wires?

Check the sparkplug, compression and injector for no.2 cylinder

Did you visually check for spark at the spark plug in question? You can use a digital multimeter, one lead touches the spark plug wire, don't take the wire loose or penetrate the insulation, the other leads goes to ground, metal part of engine. Engine running, This is an inductive reading, may show around 1/2 volt, compare to other plug wires. This test isn't conclusive, but, is non-invasive. An example, if the reading on 5 plug wires is around 1/2 volt and the other shows zero volt, I know where to start.

I didn't see you Raz, have a good day.

https://www.2carpros.com/articles/engine-hesitates

Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing.

Your best shot is have the fuel system flush out-

Dealership or to a reputable auto shop that has the equipment

Went thru a similar deal w/ '03 Ford Escape 3.0 V-6

Repetitive, fast hesitations (stumbles), lasting 1-2 seconds, varied in how far the "sets" were apart, it was more evident climbing a incline, while slowly administering gas. Random or none on level ground. Every now and again at idle, but very seldom.

---No codes --- (cleaned 1st, and/ or replaced the following

New Plugs. Then changed to "genuine plugs". Bah-Hum-bug, nothing wrong with the other new ones, I previously installed!

Boots and springs (possible holes in boots. NOT!)

air filter

MAF

EGR

A new IAC just for Giggles!

Mega Vacuum leak search several times.

Fought with wife many times over the situation, for 2+ months, It was NOT GONNA WHOOP ME!

I really hated taking off the "Plenum" so many times to access the other 3 cylinders

Each part seem to fix it for a day or two.I did not mind replacing the suggested parts, as I am all for "PM" and she's got 100,000 miles on her rig.

The final cure was #3 misfiring (lucked into the correct cylinder) I was gonna swap a new coil pack down the line, till it stopped

#3 was the ticket!

I had tried to get the Technical school to ride me with their portable machine---things did not work out, with their schedule.

I went to a salvage yard to get a used pack ($10) to swap around, then buy a new one if solved the problem.

The Master plan was to swap thru the front 3, if no positive results. Remove the plenum, "One Last Time", put the 3 front, EZily accessed packs under the plenum. Re-install it. Then swap thru the 3 front ones again (now the previous rear ones). THAT WAS THE PLAN ANYWAY.I HAVE PLENTY OF TIME, JUST NOT A BUNCH OF MONEY!

So happened, the salvage yard guy had a "SNAP ON" machine, he found a stored code, it said #3 had misfired. My little scanner could not tell me that!

Runs perfect now, with the New $79 Coil Pack!

That's why I'll always stick with a Jeep CJ, You can just about diagnose them, as you hear 'em drive by!

The Medic