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Jeep Wrangler Engine Misfire | Everything You Should Know

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One of the common problems in a jeep wrangler is an engine misfire which can affect to a greater extent the drivability of your jeep wrangler. 

For simplicity, an engine misfire is an ill condition where the air-fuel ratio in a particular cylinder fails to ignite appropriately or does not ignite at all.


Signs of a jeep engine misfire 

This results in an engine misfire that can be easily noticed as vibration, slight shaking, or rough idle accompanied by total loss of engine power.

Sometimes, it may also cause difficulty in starting your wrangler or causing the engine to stall occasionally.

Although an engine can continue to drive and operate with a misfire, the performance, exhaust emission, and fuel economy will suffer the consequences.

Sometimes an engine misfire can cause total damage to the engine in a very severe situation. This article will outline the common problems that can cause an engine misfire on a jeep wrangler and possible steps needed to solve the issue.

Scanning for Diagnostic Fault Codes

The first thing to do when experiencing the symptoms of an engine misfire is to scan the wrangler computer for diagnostic fault codes.

With the help of an OBD-II code scanner or scan tool, plug the OBD-II code scanner into the diagnostic port located under the wrangler driver’s side dash, the fault codes will display on the screen of the code scanner.

The code scanner identifies codes such as P0301, P0302, P0303, P0304, P0305, P0306, etc., which indicates a misfire in cylinders one, two, three, four, five, and six, respectively.

Although the code scanner may not specifically show the main reason for an engine misfire, it will narrow down and indicate the cylinder experiencing a misfire issue and state efforts to diagnose the problem.

Common Problems That Can Cause Jeep Wrangler Engine to Misfire

Several things can cause an engine misfire and the code to trigger on the jeep wrangler. Ranging from the spark plugs, ignition coil, the fuel system, etc.

Here are the common problems that may likely cause an engine misfire, arranged from the most likely to cause engine misfire to the least likely.

Bad Spark Plug

Spark plugs are one of the most common culprits when it comes to engine misfire problems. You may need to remove the spark plugs and inspect the electrodes to confirm whether they are in good shape or not.

Mostly, spark plugs may get worse with age, causing the engine to misfire. So this is a good place to start detecting the cause of the engine misfire.

Bad Spark Plug Wire

Another common cause of engine misfire is the spark plug wire. Spark plug wires tend to go bad after a long period, preventing or limiting the transfer of the needed voltage to arc the spark plug and ignite the air-fuel mixture.

Inspect the plug wires for traces of cracks or any form of damage, and you can also check the internal resistance of each plug wire with a digital multimeter and replace them if necessary.

Vacuum Leak

If your wrangler suffers from a vacuum leak, you will most likely have an engine misfire problem due to an improper air and fuel ratio mixture.

Most leaks occur around a specific cylinder on the intake manifold. Inspect each cylinder for possible vacuum leaks and fix the leaks to eliminate the engine misfire problem.

Bad Ignition Coil

Most wranglers are designed such that the ignition coils are easily accessible to ensure regular inspection. The ignition coils are responsible for the production of the electrical current.

The individual coil can suffer damages as well. Inspect the coil for cracks or splits and the coil body, because they are susceptible to cracks from heat as well as age.

Ensure that the electrical harness of each ignition coil is firmly plugged in. Ignition coils should be replaced if detected as the culprit

Low Compression

Low compression may be caused by several things such as cracked head, bent valve, leaking head gasket, etc.

As a result, this will cause compression not to be sufficiently high as it should, thereby causing engine misfire.

Crank Sensor

The crankshaft position sensor keeps a check on the crankshaft position, balance and rotational speed. Therefore, it sends this information to the powertrain control module (PCM) where the appropriate ignition timing and fueling are determined for complete combustion.

A failing or faulty sensor may cause engine misfire and general stalling when driving. But a wrangler will not move with a failed crankshaft sensor.

Faulty Fuel System

A faulty fuel system may trigger engine misfire on multiple cylinders. This is often caused by insufficient fuel pressure to the injectors. Thereby causing the engine to misfire during heavy acceleration or when loaded.

Low fuel pressure may sometimes allow your wrangler to drive fine while crushing or at lower RPMs. But the need for sufficient fuel pumping may not be met when driving at higher RPMs, resulting in engine misfire stalling if severe.

Common Possible Solutions

A good way to start is to carry out a diagnostic scan to detect which cylinder is affected. This will help you narrow down your options as to where the problem is.

Carry out a proper inspection on the systems mentioned above for possible causes of the misfire. Check the ignition system around the cylinder to confirm if you need to replace the plugs, wires, or coils.

Check the fuel system to ascertain everything is in proper shape. If not, replace any damaged or faulty part in the fuel system. In most cases, the culprit is always among those mentioned above.

How Much Does Engine Misfiring Inspection Cost?

There is no definite answer to how much engine misfiring inspection costs. It depends on the service center carrying out the inspection and your location.

However, engine misfiring inspection costs averagely between $65 to $100 depending on your location. While some service centers may offer you discounts and low rates if you have been patronizing them before.

Average Costs to Fix a Wrangler Misfire

The average cost of fixing a wrangler misfire can be as cheap as $35 and as expensive as $1,500. It all depends on the level of damage done, while sometimes you may just be replacing the spark plug or gasket to fill a relatively cheap leak.

On the other hand, you may be replacing an expensive system such as the fuel system or even two or three systems depending on the severity of damage done.

Is Jeep Wrangler Engine Misfire a Serious Concern?

An engine misfire is a cause for serious concern. It can make you stranded or even render the car undrivable if left unattended to.

Fixing the cause of the engine misfire as soon as you can will save you money and time. Not only that it will keep your wrangler from breaking down totally.

A quick and immediate fix will also save you other parts of your wrangler from being affected. Especially the catalytic converter and the whole engine of the wrangler can be saved from damaging.

So if you are experiencing an engine misfire on your wrangler, get it fixed as soon as you can.


When you experience engine misfire, it may be fuel or ignition related. It can be easily noticed by the loss of power in the appropriate portion, which can be relatively cheap to fix if attended to immediately.

However, forcing your wrangler to drive with an engine misfire may aggravate damage and be financially tiring to fix.

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