Where is the # 1 plug wire located on the distributor cap on a 3.4 chevy v6 1993 chevy mark3 van

missing is not always the plugs ,HT leads distributor . Most times it is from misfiring injectors and low fuel pressure.

if it is a vortec motor the wire numbers are on the cap 3 on one sid 4 on the other one of them being the coil wire

firing order is 1 8 4 3 6 5 7 2 standing in front of truck. cylinders on passenger side facing you are 2 4 6 8 cylinders on driver side facing you are 1 3 5 7 now this is your spark plugs wires location on distributor cap.with distributor facing you.2 plugs wire on cap 6 oclock position 1 plug wire on cap 8 oclock position,8 plug wire on cap 9 oclock position,4plug wire cap 10 oclock position,3 plug wire on cap 12 oclock position,6 plug wire on cap 1 oclock position, 5 plug wire on cap 3 oclock position, and 7 plug wire on cap 5 oclock position. in order for this to work you must be standing facing the engine all plug wire location on cap should be correct.

Did it backfire beofre you did the service? I'm guessing you have the wires mixed up.

Firing order 1-6-5-4-3-2, Distributor rotates clockwise

Hope this helps.

Here is the firing order for the 1994 Chevrolet Lumina APV Van with a 3.1 Liter engine with a distributor, and the 3.8 liter engine had the coil packs, and let me know if you need any help to understand this diagram, or if you require any further assistance.

GET A PIECE PAPER DRAW A LARGE CIRCLE TOP UPPER HALF CIRCLE LEFT TO RIGHT WRITE NUMBERS 1 AND 3 BOTTOM HALF CIRCLE LEFT TO RIGHT RIGHT NUMBERS 2 AND 4 THAT YOUR DISTRIBUTOR SPARK PLUGS WIRES LOCATION.STANDING ON SIDE OF ENGINE WHERE DISTRIBUTOR IS LOOKING DOWN AT DISTRIBUTOR 1 AND 3 FIRST TWO SPARK PLUGS TERMINALS NEXT TO ENGINE. AND 2 AND 4 SPARK PLUGS TERMINAL ON CAP FACING YOU. THIS IS CYLINDERS LOCATIONS STANDING IN FRONT OF ENGINE.RUN WIRES FROM DISTRIBUTOR CAP TO PLUGS TO THE ENGINE SPARK PLUGS.

1-8-4-3-6-5-7-2 The #1 spark plug is the front spark plug on the drivers side and the cylinder location in order from front to back on the drivers side is 1-3-5-7 and on the passenger side it is 2-4-6-8. The ignition rotor rotation is clockwise.

If your Distributor cap is not numbered then replace the new wires, or transfer the old ones to the new distributor cap one wire at a time. Identify the #1 spark plug wire and start from there.

You have to remove the interior dog box and the distributor and coil assemblies are in the back of the engine behind the upper plenum.

The distributor cap, spark plugs and wires are inside the van and you need to remove the glove compartment first then the heating duct then the hood. All this is located inside the van when these things are done you will see the distributor cap.

More than likely it's the distributor. They have a tendency to build up corrosion and rust and have personally went through the same situation three weeks ago on a suburban. Check to see if you are getting spark from the distributor first. Have the ecm in the distributor checked at Oriellys for free. It's under the rotor and has two 8mm head bolts with wires plugged in at each end.