2010 misfire on no 4 cylinder.

Plumpurplecrazy

Plumpurplecrazy

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San Antonio
Okay so I have a 2010 jeep jk 2 door with a 3.8l auto. I keep having misfiring problems and I have changed the coil pack twice the wires twice and all spark plugs with the required champion double platinum plugs twice also. I also changed the injector on cylinder #2 because the exhaust temp on that cylinder was 115 degrees and all other cylinders are at 315 degrees about 2 minutes idling coming out of cylinders. And after changing the injector it ran great for 17 miles or so. Now it says I have a misfire on cylinder number 4 and I checked the plug it had no spark but the coil pack and wire have spark, so I changed the spark plugs again and got spark. Installed into head and still the same misfire on cylinder number 4. Any ideas on what the problem is.
 
Plumpurplecrazy said:
Okay so I have a 2010 jeep jk 2 door with a 3.8l auto. I keep having misfiring problems and I have changed the coil pack twice the wires twice and all spark plugs with the required champion double platinum plugs twice also. I also changed the injector on cylinder #2 because the exhaust temp on that cylinder was 115 degrees and all other cylinders are at 315 degrees about 2 minutes idling coming out of cylinders. And after changing the injector it ran great for 17 miles or so. Now it says I have a misfire on cylinder number 4 and I checked the plug it had no spark but the coil pack and wire have spark, so I changed the spark plugs again and got spark. Installed into head and still the same misfire on cylinder number 4. Any ideas on what the problem is.
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Try swapping no4 plug and wire with the one next to it and see if the problem stays at 4 or moves.
 
Plumpurplecrazy said:
Okay doing that now
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Okay so I swapped the wires and now there is no misfire just drove all around town even went mudding on some back roads and it's fixed. I don't understand though all I did was swap the wire with the number 2 wire.

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Plumpurplecrazy said:
Also what is cel's??
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CEL's is check engine light, Is that light on? Also alot of time when you do any electrical replacement on the engine you need to do a battery reset.

wranglerjkforum.net

How to Reset the ECU on a Jeep Wrangler JK

While there are folks that swear resetting your ECU does absolutely nothing, it's a common practice among automotive enthusiasts. The ECU (Electronic Control Module) "learns" your driving style and the parts in your ride by storing information in its memory, information that it gathers using a...
wranglerjkforum.net wranglerjkforum.net
 
BLACKJKU said:
CEL's is check engine light, Is that light on? Also alot of time when you do any electrical replacement on the engine you need to do a battery reset.

wranglerjkforum.net

How to Reset the ECU on a Jeep Wrangler JK

While there are folks that swear resetting your ECU does absolutely nothing, it's a common practice among automotive enthusiasts. The ECU (Electronic Control Module) "learns" your driving style and the parts in your ride by storing information in its memory, information that it gathers using a...
wranglerjkforum.net wranglerjkforum.net
Click to expand...
Okay thank you and yes it's on for a lot of reasons but it was just dinging and flashing at me. Also it would pop and backfire when I would give it gas to take off and then the motor shakes convulsively when it would get to cruising speed.
 
Plumpurplecrazy said:
Okay thank you and yes it's on for a lot of reasons but it was just dinging and flashing at me. Also it would pop and backfire when I would give it gas to take off and then the motor shakes convulsively when it would get to cruising speed.
Click to expand...


It's popping and back firing now? Why don't you do a reset like in the link I gave you and then drive it.
 
Plumpurplecrazy said:
No it was popping and backfiring before I swapped the wires like you said and I'm going outside to reset it right now. Thank you very much
Click to expand...

So you only swapped the wires and not the spark plugs? If that's the case maybe no 4 plug wire wasn't pushed on all the way.
 
Well I just reset the ecu and then drove it about 2 miles to the gas station put 20 bucks in it and when I started it back up it was missing againg and is popping and backfiring again. Any other ideas?
BLACKJKU said:
So you only swapped the wires and not the spark plugs? If that's the case maybe no 4 plug wire wasn't pushed on all the way.
Click to expand...
 
Chances are then since it's staying at no 4 it could be the injector or the electrical connector on the injector.
 
Okay so all the injector plugs read the same voltage give or take .4 11.8v to 12.2. replaced injector and still was misfiring. So I started to inspect the wire to cylinder 4 and saw that it was a little melted. Then I went back and saw that every wire I have put on this cylinder is melted. I went to oriellys and got a heat shield for the wire and installed the wire been driving all day put almost 50 miles on it and still running good. Thank you for your help and I'm sure I'll be back with other problems.
 
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