New Plugs/Coils now strange idle

[StrayKatJJL]

2006 Liberty 3.7 170,000 miles. I had to turn around on the way to work last week from engine light and engine acting weird. I pulled my code and got P0304 misfire on my 4th cylinder. I pulled the coil and moved it to 2nd cylinder and the code followed it. I decided to just replace all plugs and coils. Now my idle is a bit rough and seems to jump rpm up now and then. I'm confident in the service I did. I it necessary to 'kill' the computer so it can re-register the new plugs and coils? Holding negative to block for 30 seconds? Thanks

 

[Ksat]

Most people on here report better luck with using the regular copper plugs (any cheap name brand will do) instead of the more expensive precious metal varieties. Gap to 0.040", I believe.

Chryslers apparently have the rep of disabling the coil control once it detects an ignition coil-related problem, but usually just a cycling of the key will clear that up. Erasing the code or touching the battery cables together (disconnect from battery 1st, of course) wouldn't hurt, either.

Are you getting any new codes since the plug and coil replacement? What brand of coils did you replace with?

 

[StrayKatJJL]

Most people on here report better luck with using the regular copper plugs (any cheap name brand will do) instead of the more expensive precious metal varieties. Gap to 0.040", I believe.

Chryslers apparently have the rep of disabling the coil control once it detects an ignition coil-related problem, but usually just a cycling of the key will clear that up. Erasing the code or touching the battery cables together (disconnect from battery 1st, of course) wouldn't hurt, either.

Are you getting any new codes since the plug and coil replacement? What brand of coils did you replace with?

I think i drained the battery while doing the compression test, although it started fine, I proceeded to do a full charge last night and did touch the pos - neg terminal for 5 min to clear the computer. This morning Jeep drives like new. So it may have been a bit of both? Ill pull my codes in a couple days, curious if there is anything there. thanks for the reply

 

[Xterra4x4]

2006 Liberty 3.7 170,000 miles. I had to turn around on the way to work last week from engine light and engine acting weird. I pulled my code and got P0304 misfire on my 4th cylinder. I pulled the coil and moved it to 2nd cylinder and the code followed it. I decided to just replace all plugs and coils. Now my idle is a bit rough and seems to jump rpm up now and then. I'm confident in the service I did. I it necessary to 'kill' the computer so it can re-register the new plugs and coils? Holding negative to block for 30 seconds? Thanks

A possiblity coil is bad even if you bought new! What brand are they? Autozone no good

 

[StrayKatJJL]

Most people on here report better luck with using the regular copper plugs (any cheap name brand will do) instead of the more expensive precious metal varieties. Gap to 0.040", I believe.

Chryslers apparently have the rep of disabling the coil control once it detects an ignition coil-related problem, but usually just a cycling of the key will clear that up. Erasing the code or touching the battery cables together (disconnect from battery 1st, of course) wouldn't hurt, either.

Are you getting any new codes since the plug and coil replacement? What brand of coils did you replace with?

Yes that would be another possibility and I did use the Autozone coils. However since charging my battery and doing the computer purge the Jeep is running fantastic. In fact I drove 140 highway miles and discovered Im now getting 21 mpg up from about 18

 

[Xterra4x4]

A possiblity coil is bad even if you bought new! What brand are they? Autozone no good

Well after plug and coil replacement it takes a few secondss for computer to reset!