97 dodge dakota. 2.5 , 5 speed, 2wd, 110k . I have replaced - dist. cap, rotor,wires, plugs, fuel pump, fuel filter, # 4 injector, tps, crank pos sensor, air filter. Truck will start and run fine until warm, then occasionaly when driving at midrange rpm, the truck will buck and miss and backfire, then clear up and drive fine for a while. the ais is making normal steps. no apparent vacum leak. checked harness and connectors they appear fine, then replaced pcm. Truck ran fine for two weeks, now back to same problem.

you may have a plugged fuel filter as you don`t say if you have changed it. also have your fuel pressure tested with a gage, it should run about 36 lbs pressure if its multi-point fuel injection or run at about 15/18 lbs pressure if its a throttle body.

Spark Plugs?

Their is no pickup coil,You have a crank sensor

Their is a Hall Effect Sensor in Dist for Injector timing?

If you move the Dist your done. Has to set with a Volt meter

could it be your crank sensor?
having a similar problem with a dakota. dodge tells me it may be the dist, but seeing as how you replaced it with a new one it could be that the sensor needs replacing

SLUGGLISH ENGINE COULD BE STOPPED UP FUEL FILTER AND FUEL INJECTORS.YOU COULD HAVE LOW TRANSMISSION FLUID LEVEL OR TRANSMISSION FILTER NEED CHANGING.OR YOU HAVE RESTRICTED EXHAUST MUFFLER OR CATALYTIC CONVERTER.

Have you had the computer scanned? It sounds like a fuel injector problem. Injectors may be dirty. Or possibly a fault in the injector circuit. You didn't mention changing the fuel filter. I know some of the Dodges have the filter integrated with the pump. If yours has an independent filter it should be replaced.

Check all the sensors

Could be plugged fuel filter, faulty fuel pressure regulator (check your pressure) and most probable is a sticky or dirty injector. Do check your timing as well.

replace the air filter,pcv valve and spark plugs if over 60 k and the wires are original replace dist cap rotor and wires also then clean the throttle bore spotless with cab cleaner and a rag scan for any codes and sensors out of range there is no fuel filter (it is part of the fuel pump)

First of all let's explain how the spark gets to the plugs. There is a crankshaft position sensor and a cam sensor. They are what determines when to fire the coils and injectors. The crank sensor is located on the passenger side on top of the bellhousing, the cam sensor is the pickup plate in the distributor. As the engin turns the send refernece pulses to the computer which grounds and ungrounds the ignition coil causing it to discharge and send voltager from the secondary coil wire to the center tower in the distributor cap. The rotor button recieves the voltage and distributes it to the 6 towers (1 for each cylinder) If you say you're getting spark from the rotor that tells me the primary side of the ignition system is working, and the secondary side is working into the distributor cap. I'd check for spark out of the plug wires at the plugs. Pull a wire and insert a #2 phillips screwdriver into it, hol the shaft of the screwdriver aprox 1/8"(no more) from the exaust manifold and observe the spark as someone turns over the engine. You should see a nice blue spark. If theres spark, spray a little gum cutter in the throttle body an crank it, if it fires you have a fuel problem. Install a fuel pressure gauge on the schrader valve on the fuel rail and observe it as you crank it. If theres no fuel pressure maks sure there's fuel in the tank, if so climb underneath and beat on the bottom of the tank with a rubber hammer, the pump may be going bad, sometimes you can jar them and make them run.

Check fuel filter and air cleaner, fuel pump or fuel pump relay