[bstone]

I got a code last week that Cylinder 1 was misfiring. I replaced both the plug and the fire, cleared the code (I have my own OBD II scanner) and it went away for about 200 miles. Now today it's back. Since I already replaced the plug and wire I am at a loss of what to do next. Help?

 

[phantom]

It could be the coil or an injector but I am curious what brand of spark plugs did you use ?

 

[bstone]

I used Bosch plugs and wires. I have them in the other sockets and they are fine.

 

[phantom]

Bosch platinum plugs with the pointy tip electrodes are problematic to put it nicely.I would always recommend to go back with factory spark plugs which would be motorcraft.I would remove the spark plug and inspect it due to the design it only takes a small piece of carbon to cause a problem.

 

[theoldwizard1]

"Misfire" is not an "accurate" term. It should say "incomplete combustion".

The plug can be firing just fine and you can still get incomplete combustion by a valve not fully closing or an injector notsquirting properly.

If possibly swap the injector to another cylinder and see if the fault moves with it. If you have coil-on-plug you can do the same.

 

[bstone]

How do I swap the injector? Sorry, I am a big noob in all of this.

 

[phantom]

On that bank you would have to remove the upper intake,temove the 2 8mm bolts holding the fuel rail and you can swap them around.I would swap sparkplugs it would be easier if the misfire moves its a plug if it stays #1 thrn yry the injector swap.

 

[bstone]

Well I drove 140 miles last night and the engine light did not come back on. This is mildly confusing.

 

[oldtimer35]

What are you driving? Could this be a problem with egr flow. Some motors have a tendency to plug the egr ports in the lower intake, if that is the design of the motor, and you will get a misfire on what ever port is still open, because it will be too much flow for one port. Try pulling a slight vacuum on the egr to see if you get the miss on the same cylinder. :wink5:

 

[bstone]

I've already replaced the EGR valve, sensor and solenoid in the past month. I was getting codes for it but no longer.

 

[bstone]

I just replaced the plug and the wire with an Autolite XP iridium "extreme performance" plug and a stock wire they had at AutoZone. I cleared the code, ran it for 30 seconds in park while giving it some gas and the light came back on. Still reading as Cylinger 1 misfire. I guess I'll have to figure out how to move the fuel injector. Never done it before.

 

[Canuck623]

I don't mean anything by this but I have to ask because a lot of people mix this up. What plug and wire are you calling #1?

 

[bstone]

I don't mean anything by this but I have to ask because a lot of people mix this up. What plug and wire are you calling #1?

On the coil there is a #1 with an arrow to the plug wire. I followed that one and replaced the plug and the wire. I think I got the right one. #1 is on the passenger side close to the firewall.

Is that correct?

 

[Jonzo77]

Bosch platinum plugs with the pointy tip electrodes are problematic to put it nicely.I would always recommend to go back with factory spark plugs which would be motorcraft.I would remove the spark plug and inspect it due to the design it only takes a small piece of carbon to cause a problem.

motorcraft and Autolite... they're both the same, just different name...
just like mopar used champion, and GM has AC-Delco.

 

[Jonzo77]

On the coil there is a #1 with an arrow to the plug wire. I followed that one and replaced the plug and the wire. I think I got the right one. #1 is on the passenger side close to the firewall.

Is that correct?

What engine is in it? i'm not familiar with the tore-a$$...

 

[bstone]

motorcraft and Autolite... they're both the same, just different name...
just like mopar used champion, and GM has AC-Delco.

So you're saying I replaced the spark plug with something that is known for having the same exact problem? Ugg. There's more wasted money.

Can you please make a specific recommendation for a spark plug that you know won't have the issues?

 

[Canuck623]

On the coil there is a #1 with an arrow to the plug wire. I followed that one and replaced the plug and the wire. I think I got the right one. #1 is on the passenger side close to the firewall.

Is that correct?

Yes that is the right one. Good. You have no idea how many people think bank one is the front of the engine. I read this thread but can't remember seeing if you replaced the coil or not? Are you getting good spark at that wire? Pull it off the plug and get a spark tester from any parts store and test it. If you have good spark with a tester at the plug end of the wire the coil and wire are ok. No spark then you need to check it at the coil end of the wire. Good spark there = bad wire. No spark there = bad coil. I doubt that you would replicate the same misfire over the span of two or three different plugs so for the sake of diag don't change them again. You could swap #1 with #4 to see if the miss follows it but I doubt that will happen. I do agree that Motorcraft plugs are the best. Autolite, contrary to popular belief are no longer made at the same factory as Motorcraft and are not related any more. The Autolite is an ok plug but not as good as OEM. Okay, back to the diag. If you have good spark to the plug we are looking at either a fuel issue or a base engine problem. Fuel injectors are hard to swap around but it is a good test. If the miss follows the injector you know what is next. If you have or can borrow a scan tool that will monitor basic PID's set it to watch the injectors for faults. If it counts any faults you need that injector. The free scans at AZ and other places won't tell you anything, nor will the hand helds that you can buy for a couple hundred bucks. What I would do first is a compression test on the engine. Pull all the plugs and check it with the throttle wide open. A common issue that causes a misfire is broken valve springs. Compression test will tell you a lot. If it is low on #1 pull the cover and have a look. Compression ok and I think we are looking at a fuel injector faulting enough to alarm the PCM. Don't over look fuel pressure either. Low pressure will usually affect an entire bank but it could single out a weak injector.

 

[bstone]

Yes that is the right one. Good. You have no idea how many people think bank one is the front of the engine. I read this thread but can't remember seeing if you replaced the coil or not? Are you getting good spark at that wire? Pull it off the plug and get a spark tester from any parts store and test it. If you have good spark with a tester at the plug end of the wire the coil and wire are ok. No spark then you need to check it at the coil end of the wire. Good spark there = bad wire. No spark there = bad coil. I doubt that you would replicate the same misfire over the span of two or three different plugs so for the sake of diag don't change them again. You could swap #1 with #4 to see if the miss follows it but I doubt that will happen. I do agree that Motorcraft plugs are the best. Autolite, contrary to popular belief are no longer made at the same factory as Motorcraft and are not related any more. The Autolite is an ok plug but not as good as OEM. Okay, back to the diag. If you have good spark to the plug we are looking at either a fuel issue or a base engine problem. Fuel injectors are hard to swap around but it is a good test. If the miss follows the injector you know what is next. If you have or can borrow a scan tool that will monitor basic PID's set it to watch the injectors for faults. If it counts any faults you need that injector. The free scans at AZ and other places won't tell you anything, nor will the hand helds that you can buy for a couple hundred bucks. What I would do first is a compression test on the engine. Pull all the plugs and check it with the throttle wide open. A common issue that causes a misfire is broken valve springs. Compression test will tell you a lot. If it is low on #1 pull the cover and have a look. Compression ok and I think we are looking at a fuel injector faulting enough to alarm the PCM. Don't over look fuel pressure either. Low pressure will usually affect an entire bank but it could single out a weak injector.

I've already replaced both the plug and the wire, so the only other spark problem would have to be the coil. I'll pull #1 and to a spark test on it to see if it is properly sparking.

I saw a video on how to do a compression test (Scottie Kilmer on youtube) so I'll follow those steps. Hopefully it's a fuel injector problem and not a valve problem. I've never rebuilt an engine- don't know where to start. I don't even know how to swap the fuel injectors, but assume that I can figure it out with some great guidance here!

 

[bstone]

I took out the Autolite spark plug and replaced it with a Motorcraft spark plug. This one.

I then drove from New Haven, CT to Boston, MA, about 130 miles. The engine did well but I *briefly* got an engine light when I stopped to get gas. The light flashed a bunch of times and then went away.

I have a sneak suspicion that the plug and wires are fine, but that this is a coil or injector problem.

Can someone help me with an injector inspection/swap? Pictures would be amazing.

 

[Canuck623]

I took out the Autolite spark plug and replaced it with a Motorcraft spark plug. This one.

I then drove from New Haven, CT to Boston, MA, about 130 miles. The engine did well but I *briefly* got an engine light when I stopped to get gas. The light flashed a bunch of times and then went away.

I have a sneak suspicion that the plug and wires are fine, but that this is a coil or injector problem.

Can someone help me with an injector inspection/swap? Pictures would be amazing.

Hope ths helps.