Whats is the proper spark plug gap for an 06 Ranger 4.0

The proper spark plug gap for your 1998 Ford Ranger 2.5L with 8 plugs depends on the specific spark plugs you're using. Here are some recommended gap values:

Champion RC8PCY: Gap of 0.8mm.
NGK PFR6B-II: Gap of 1.1mm.

It depends on the spark plugs that have been used. Some are pre gapped, some have three preset side electrodes around the edge. Gapping spark plugs is not as critical as the old days due to modern CDI ignition systems which give a much larger spark and huge improvements in spark plug technology.

https://www.google.com/search?q=1993+Ford+Ranger+4.0+spark+plugs

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Ignition System Specifications
Application
Specification
Metric
English
Firing Order
1-6-5-4-3-2
Spark Plug Gap
1.52 mm
0.060 in
Spark Plug Torque
15 N·m
11 lb ft
Spark Plug Type
GM P/N 12568387
Spark Plug Wire Resistance
3000 ohms per ft

0.044", IT16 Denso Iridium Spark Plugs are the best for your truck... they last 60K miles on average, save gas and add power.
Use thread antisieze lube on the first 2 to 3 three threads of the spark plug, it makes it easier to remove them in 5 or 6 years time. Check your plug wires one at a time too for signs of wear and cracking at the boots. A peak inside the distributor cap is also a good practice... any black carbon deposits at the electrodes is a sign it needs replacing along with the rotor. Your truck has a 2.3 liter, 4 cylinder engine.

1.10 mm

Tune Up

Spark Plug

AWSF-42C

Spark Plug Gap

0.044

Ignition Timing

10 degrees BTDC

Firing Order

1-4-2-5-3-6

Distributor Rotation

Clockwise

Valve Clearance Intake

0.014

Valve Clearance Exhaust

0.016

0.042-0.046 is the correct gap for your spark plugs,If it is backfiring now and was not before make sure you were not sold platinum bosch plugs and if you are using factory plugs,then I be looking for a faulty spark plug.Also make sure the firing order is correct.

SPARK PLUG GAP SETTING IS 2.4L ENGINE GAP SETTING IS 0.050 FOR THE 2.2L ENGINE SPARK PLUG GAP IS 0.060

Hi!1
The spark plug gap is 044 (In thousandths of an inch) Caution! Gap is not adjustable on certain plug brands. The 4 cyl. 2.3 L engine uses 2 spark plugs per cylinder.
A HELPFUL - 4 THUMBS - rating for this solution would be greatly appreciated. Thank you for using FixYa.

it realy wont bother the car to much what you set it at but go for a gap of 18 to 25 th of an inch