Need help with engine misfire

andy0469

andy0469

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Joined
Dec 19, 2023
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Willemstad, Curacao
My 2008 jeep JK wrangler. losses power when I put it into drive. I sent the jeep to the shop, the mechanic told me that the jeeps computer was the problem, I bought a new computer and installed it but the car remained doing the same thing. Bought a coil pack (a year ago) but I can't believe that the coil pack is already damaged could that be possible?....what are some other known issues that can cause this problem? as soon as I put the jeep into "Drive", My RMP starts moving up and down. It then stops for a while and then begins to move up and down again. Also my motor misfire !


!!!!PLEASE CHECK VIDEO IN RESPONSE BELOW FOR AN UPDATE!!!!
 
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1) If you keep it in park or neutral but try increasing the engine rpm what happens?

2) How about reverse? Same thing as drive?

If the answer to question #1 is that is the engine won't rev freely you should check the usual suspects - air, spark, fuel. Maybe something like the electronic throttle body or sensor, fuel pump going bad, etc. Lots of variables and possibilities here, unfortunately. Your statement about the engine misfiring makes think there is an underlying issue.

If the answer to #1 is that it revs freely but the answer to question #2 is that it does the same as in drive you could have
an issue with the torque converter...

Hard to diagnose something like this but the more info you provide the more we can try to guide you.
 
tJKrider said:
1) If you keep it in park or neutral but try increasing the engine rpm what happens?

2) How about reverse? Same thing as drive?

If the answer to question #1 is that is the engine won't rev freely you should check the usual suspects - air, spark, fuel. Maybe something like the electronic throttle body or sensor, fuel pump going bad, etc. Lots of variables and possibilities here, unfortunately. Your statement about the engine misfiring makes think there is an underlying issue.

If the answer to #1 is that it revs freely but the answer to question #2 is that it does the same as in drive you could have
an issue with the torque converter...

Hard to diagnose something like this but the more info you provide the more we can try to guide you.
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I just bought a new coil pack and new spar plug cable! Good news, the engine is not misfiring anymore, and the RPM is now stable. SIDE NOTE: I bought a new throttle body a couple a months ago at the jeep agency here.

HOWEVER, after changing and adding the new (MOPAR) coil pack & spar plug wires, my engine started shaking when I put it into gear! when its in park or neutral is does not shake. It only shakes when I put in gear and reverse! When I put gas to drive it doesn't shake anymore.

im going to copy paste a link of the video I recorded when the engine is in gear and how it stops when its in neutral/park

HERE IS THE VIDEO. LET ME KNOW! AND THANK FOR REPLYING !!
 
Dirty Dog said:
Bad motor mount or transmission mount would be my first guess.
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That's a good guess.
andy0469 said:
BUT It only shakes when its in gear and reverse! will it still stay the same?
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In neutral or park there is virtually no load on the engine. Once you put it in drive/reverse you've loaded the engine and are at a low rpm, which is directionally bad for vibrations. The mounts are the only thing that are counteracting the shaking force at that point. A bad mount will not adequately absorb the vibrations and send them through the chassis to be felt by the driver.
 
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When you have any electrical problems for the engine, things that require 12v to make the engine function you should always have a CEL light. Then you can have the CEL's read and it will let you know the issue.
 
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BLACKJKU said:
When you have any electrical problems for the engine, things that require 12v to make the engine function you should always have a CEL light. Then you can have the CEL's read and it will let you know the issue
Click to expand...
Okay...I do have an update. the engine isn't shaking as much as yesterday. its stops for a while then it starts trembling a little again. LEss compared to yesterday !! Should I also buy new spar plugs just incase and see for myself before I send it to a mechanic and check all the other things mentioned above? Spar plugs I currently have right now are more than a year old if im not mistaken.e
 
tJKrider said:
That's a good guess.

In neutral or park there is virtually no load on the engine. Once you put it in drive/reverse you've loaded the engine and are at a low rpm, which is directionally bad for vibrations. The mounts are the only thing that are counteracting the shaking force at that point. A bad mount will not adequately absorb the vibrations and send them through the chassis to be felt by the driver.
Click to expand...
I do have an update. the engine isn't shaking as much as yesterday. its stops for a while then it starts trembling a little again. LEss compared to yesterday !! Should I also buy new spar plugs just incase and see for myself before I send it to a mechanic and check all the other things mentioned above? Spar plugs I currently have right now are more than a year old if im not mistaken
 
andy0469 said:
I do have an update. the engine isn't shaking as much as yesterday. its stops for a while then it starts trembling a little again. LEss compared to yesterday !! Should I also buy new spar plugs just incase and see for myself before I send it to a mechanic and check all the other things mentioned above? Spar plugs I currently have right now are more than a year old if im not mistaken
Click to expand...


Another thing you could do is add a yellow bottle of Heet to your fuel tank, could possibly have some water in your fuel tank. If your not having a CEL light then it could be fuel related and you won't get a CEL for that.
 
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BLACKJKU said:
Another thing you could do is add a yellow bottle of Heet to your fuel tank, could possibly have some water in your fuel tank. If your not having a CEL light then it could be fuel related and you won't get a CEL for that.
Click to expand...
My CEL light has been on since I bought the jeep. Went to the shop, got scanned by a computer but nothing came up. it's been years now to be honest. It now also flashes on and off, then stays on like it was before.
 
Try doing a ECM reset that should clear any CELS and then it helps the ECM reset it's self. Then if there is any electrical problems a new CEL should come up.
 
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