P0307 #7 misfire

[Trainmaster]

Lots of new bad coils out there. And too many people throw parts at a problem without proper diagnosis. Good tools are costly, but you can only get along so long without them if you do your own work. Eventually you'll get a problem that's tough and will burn up more time and money than the proper diagnosis would have cost.

 

[megan4221977]

@Trainmaster I checked the spark with tester from coil to plug and was good

 

[Trainmaster]

I checked the spark with tester from coil to plug and was good

While that may show some spark, there are much more refined testers that will actually count the number of misfiles in a period of time and log the conditions and other parameters when they occur. That's the type of equipment you need. That's how a good dealer or mechanic can pinpoint your problem without throwing parts at it.

You won't find this at a chain auto parts store or a franchised garage. Expensive stuff, but for a problem like this, it cuts through the nonsense.

 

[Planocat]

While that may show some spark, there are much more refined testers that will actually count the number of misfiles in a period of time and log the conditions and other parameters when they occur. That's the type of equipment you need. That's how a good dealer or mechanic can pinpoint your problem without throwing parts at it.

You won't find this at a chain auto parts store or a franchised garage. Expensive stuff, but for a problem like this, it cuts through the nonsense.

Couldn't agree more.....we're a long way removed from the points, plugs, and condenser era. I thought I had a good local shop but at the end of the day his equipment and ability to read it just couldn't get it done. Costly lesson on my part.

Planocat

 

[Josha907]

Plugs can be bad had one with less then 3000on it. Ground strap was gone!!kinda mad about it

 

[Stephen Dunster]

I once cracked the resistor of a new plug dropping it into the hole when installing new plugs. Ran for 400 miles and started to have an intermittent misfire. Replaced the coil, still had a misfire. Took it to the local Ford dealer and they had it fixed in about an hour.

 

[megan4221977]

@Dennis_H OMG!!! You were correct!! All that crap and was a bad spark plug!!! I never in my 30+yrs have ever had a bad one new out of box! I even checked porcelain to see if cracked, even checked the gap all was good! I was about to sell truck, so fed up!! lol

 

[megan4221977]

@Trainmaster I switched just plugs to see, and it followed! So was bad plug

 

[Trainmaster]

Glad it was a simple problem. Often is.