Why is Mazda Miata stumbling and missing after reaching closed loop?

#2 cylinder misfire. Plug, wire, or coil pack. One of them is bad. My guess is the coil pack. Pull the wire off the coil, lay it on top the coil close to the #2 port. Start the van. You should see the coil throwing an arc to the plug wire. No arc replace the coil. If you have arc, then replace the plug and wire. I would do all of them.

its a 2.0L V6 called the h20 engine
in some countries, this engine uses a coil pack with 1 coil per
2 cylinders, this magic is called Wasted spark.
some have 3 coil packs for 6 cylinders
others have 1 huge pack with 3 coils inside.
what you have , im totally clueless, (no country stated, dig?)

but no matter, the pack is bad, or the wire that is FINE, is not FINE
no human on earth can test a HV wire, no body.! ( 1 out of 4 sure)
that is fact, (sure if opened) but what about the other modal failiures.
1: insulation breakdown.
2: resistance wrong, (say too high)
3: intermittent.
4: dead open, anyone can test this, its a no brainer. if ever.

this fact is why the 60k mile tune up, will fix it. new wires.
new HV wire set, I run NGK MAG wires, they last 2x longer.
easy.

no only that. with wasted spark , the other plug in the loop can cause your dead plug to be dead. and its wires too.
that is because it is a LOOP

if both plugs are new and both wires are new
then the coil is bad.
coil packs are usually way more expensive that $2.49 spark plugs
or $20 wires.

A P0304 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #4.-------- Symptoms may include:--------

• the engine may be harder to start.
• the engine may stumble / stumble, and/or hesitate.
• other symptoms may also be present.

--------------- A code P0304 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer.
• ---------------------

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.-----------------
This should help.Thanks.Helpmech.

A P0301 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #1.



FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebook Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes:A code P0301 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible Solutions:If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Hope helps; tell us news and keep in touch (remember rated this help).

P0300 - random cylinder misfire detected

Check spark plug wire's and plug's and ignition coil. tune up should take care of it.

A code P0305 may mean that one or more of the following has happened:

Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

If it's the four cyl., the first coil pack bolts over the #2 spark plug. The #2 coil pack wire plugs into #3 spark plug. The number two coil pack bolts directly over the number four spark plug, and the #2 coil pack wire plugs into the #4 plug. The firing order is 1-4-2-3.

man read this and u will know what is ur problem and how to fix it
P0300 Code - Random Misfire What does that mean? A P0300 OBD DTC code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

CausesA code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective computer

Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

P0302 Code - Cylinder #2 Misfire
What does that mean?
A P0302 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #2
SymptomsSymptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

SymptomsSymptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

CausesA code P0302 may mean that one or more of the following has happened:

• Faulty spark plug or wire
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression
• Defective computer

Possible SolutionsIf there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Your problem sounds like an intermittent short in the power feed to the coil pack from the EEC module