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Its a 98 5.9 R/T. I've put an Accel cap & rotor, Accel coil, Taylor 8mm wires, and platinium plugs on it. It idols and runs fine til I put my foot into it. I checked the firing order its ok. Checked all the connections their ok. It flashed a random missfire in #7 & #4 cylinder code so thats why I replaced all this stuff.

Kinda baffled at this point. I think its the cat but it runs fine until i go to pass someone on the hwy. Then it acts like its not getting fire and starts backfiring. Any help would be greatly appreciated.
 

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Its a 98 5.9 R/T. I've put an Accel cap & rotor, Accel coil, Taylor 8mm wires, and platinium plugs on it. It idols and runs fine til I put my foot into it. I checked the firing order its ok. Checked all the connections their ok. It flashed a random missfire in #7 & #4 cylinder code so thats why I replaced all this stuff.

Kinda baffled at this point. I think its the cat but it runs fine until i go to pass someone on the hwy. Then it acts like its not getting fire and starts backfiring. Any help would be greatly appreciated.
Did you get the proper ACCEL coil for your 5.9?
AFIAK, there is only one ACCEL coil that is compatible with the low side coil driver in the PCM for the Dakotas using the OEM PCM coil driver.

The resistance of the primary of the coil has to be in range of what
the PCM's switching transistor expects, otherwise it may not energize
the primary of the coil properly. If that happens, the magnetic field induced
in the coils primary doesn't collapse the way it supposed to..and consequently the high tension voltage in the secondary won't be up to the proper voltage.

Since the PCM can only monitor low voltage (+12V) and cannot determine
what is happening in the distributor cap/rotor or spark plugs, it can only
post a misfire code when it's internal spark timing map and the signals it
receives from the sensors...DON"T quite match up.

A cylinder related misfire is just what it says. Cylinder #3/7 probably had
bad wires originally, as the OEM carbon resistive wires start to develop problems after a 40-50 thousand miles.

What you may have now is a advance timing issue with the spark. Since
there is no vacumn advance on the 5.2/5.9, it's all electronic advance in the
\PCM based on 3 sensors, cam/crank and TPS. The spark (advance) timing when you "step on it" has to be determined by the PCM and to some degree the
coil itself..ie the magnetic saturation within the coil.

If you still have the OEM Dodge coil, put that back on to verify if the coil
is causing your problem..otherwise, it could be: (in no particular order)

cam sensor
TPS
crank sensor.

Both the cam and crank sensor are hall effect semiconductor and have been
known to cause " weird" problems.
The TPS sensor can be checked out electrically on the vehicle before replacing.

Procedure is:
Remove air duct to get at the throttle body
Ignition on but do NOT start the vehicle
With a digital voltmeter, back probe the center wire (sensor signal)
and connect the black lead to a suitable ground
With the throttle plate fully closed..it should read 0.5volts
With the throttle plate fully open..it should read about 4.5 volts
In between there should be a SMOOTH transition on the reading from
0.5 volts to about 4.5 volts.
 
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