misfire on all cylinders on 1997 Dodge Ram Van 2500

i have been trying to figure out what is causing this misfire code. less than year ago i did plugs, wires, rotor, cap. three months ago i had a misfire cylinder 6 code and it was a bad fuel injector, so that was the first thing i changed on cylinder 4 but the code came back, the wires to the fuel injectors are fine. i did a compression test and all cylinders are around 120+psi. fuel pressure is 50psi. i also recently replaced the intake manifold gasket. i also replaced the cam and crank sensors the p1319 code went away and now i have misfire on all cylinders p0300

by in Mohnton, PA on April 14, 2011
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1 answer
ANSWER by , April 18, 2011
When you replaced the intake manifold gaskets, Di you replace the Plenum Gasket? It is located on the bottom of the intake manifold. If this gasket is leaking, you will have a vacuum leak. engine pinging and unusually high oil comsumption. Also, if by chance you removed the distributor, it will have to be re-synced with the Crankshaft Position Sensor as the distributor is a Camshaft position sensor and sync is critical to the timing of the injectors in relation to piston location. Engine timing is controlled by the Powertrain Control Module, Not the Distributor. Another posibility is that your distributor drive gear and bushing is worn. See the following Technical Service bulletin. NO: 18-08-93 Rev. A SUBJECT: Engine Buck, Surge Or Noise - Oil Pump Drive Gear Wear DATE: Nov. 26, 1993 SYMPTOM/CONDITION: Vehicle exhibits warm engine surging, light bucking, or cold engine lack of power or burst spark knock. Engine noises (light knock or tapping sound at rear of engine) may also be experienced with no driveability complaint. These conditions may be caused by excessive oil pump drive gear wear. DIAGNOSIS: Remove the distributor cap and grasp the rotor and using a rotational motion, check the total clockwise/counter-clockwise movement at the rotor tip. If the rotor tip movement is 5.0 mm (3/16") or more, proceed with the following repair procedure. PARTS REQUIRED: 1 53020546 Oil Pump Drive Gear 1 01737725 Block Bushing REPAIR PROCEDURE: This bulletin involves replacing the oil pump drive gear with a revised part and the drive gear block bushing. Remove distributor and distributor/oil pump drive gear block bushing as outlined in the appropriate service manual. *NOTE: TOOL NUMBER C-3052 (DISTRIBUTOR DRIVE SHAFT BUSHING PULLER) MUST BE USED TO REMOVE DISTRIBUTOR/OIL PUMP DRIVE GEAR AND TOOL NUMBER C 3053 (DISTRIBUTOR DRIVE SHAFT BUSHING DRIVER/BURNISHER) MUST BE USED TO INSTALL THE NEW DISTRIBUTOR/OIL PUMP DRIVE GEAR BUSHING.** Install new drive gear block bushing P/N 01737725 and revised oil pump drive gear P/N 53020546 as outlined in the appropriate service manual. **NOTE: THE CORRECT POSITION FOR THE DISTRIBUTOR/OIL PUMP DRIVE GEAR BUSHlNG IS SHOWN BELOW.**(See Illustration) Change engine oil and filter. Perform the required distributor indexing procedure as outlined in the appropriate service manual or use the alternate procedure outlined in steps 5-9. ALTERNATE DISTRIBUTOR INDEXING PROCEDURE Connect a voltmeter to the distributor sensor connector by removing the end seal and carefully back probing the connector. Connect the positive lead to the sensor output pin (pin 3, either a tan wire with a yellow tracer or a gray wire, depending on vehicle application). Connect the negative lead to the sensor ground pin (pin 2, a black wire with a light blue tracer). Rotate the engine clockwise as viewed from the front, until the number one mark piston Top (TDC) compression on the vibration damper should line up with the zero degree (TDC) mark on the timing chain case cover. Continue to rotate the engine slowly clockwise until the V6 or V8 mark (depending on engine type) lines up with the zero degree (TDC) mark on the timing chain case cover. The V8 mark is 17.5°after TDC and the V6 mark is 147° after TDC. NOTE: DO NOT ROTATE THE ENGINE COUNTER CLOCKWISE. IF THE ENGINE IS ROTATED BEYOND THE MARK, RETURN TO STEP 6 AND REPEAT THE PROCEDURE. With the distributor clamp bolt loose and the ignition switch in the ON position, rotate the distributor slightly in either direction until the voltmeter switches between the sensor transition point of 0 and 5 volts. Adjust the distributor as close as possible to either side of this transition point and tighten the distributor clamp bolt to 170-230 in. lbs. (19-26 Nm).