Changed plugs, had weird Bosch in it- pic


ALScott

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Still bringing maintenance up to date on new LJ. Changed out the plugs and uneventful. Seems to idle smoother now but idle seems low. It's dead between the two dots under 1K. Any thoughts on plugs appreciated. I have no clue when PO put these in but it was running fine with no engine light on so taking that as a plus.
IMG_1447.jpg
 

06lj

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Those plugs were just a waste of money. My LJ idles right around 750 rpm. Since your already under the hood cleaning the throttle body might improve your idle.
 

LJBean

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Still bringing maintenance up to date on new LJ. Changed out the plugs and uneventful. Seems to idle smoother now but idle seems low. It's dead between the two dots under 1K. Any thoughts on plugs appreciated. I have no clue when PO put these in but it was running fine with no engine light on so taking that as a plus.
View attachment 249672
I've not seen those before. I assume you don't need to check gap on them?
 

TheBoogieman

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These also go on sale/rebate regularly, after a rebate I paid around $2.50/plug and never expect to change them again.
I paid more at Advance auto, but I had Speed Perks money and their online 25% discount. I think I paid $22 for all six. I wish I could find an air filter that didn't need replacing for the life of my Jeep too. Pollen here is worse than the dusty crap I see. :confused:
 
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Jerry Bransford

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YOU ARE CORRECT. I RUN THE OEM NGK SPARK PLUGS. NEVER HAD A PROBLEM.
Yes those will work without problem. Their only drawback is limited life, especially on newer 4.0 engines with the waste-spark ignition system (coil rail ignition) that fires each plug twice as often which results in half the life for the spark plugs.

If you go with double-platinum plugs like Autolite's APP-985 or Champion's 7412 you'll get 100k miles of "NEVER HAD A PROBLEM" instead of 20-25k. With Autolite's iridium XP-985 you'll get 200k miles of "NEVER HAD A PROBLEM". Personally I've been running the XP-985 since probably 2003 or 2004.

Incidentally, Bosch spark plugs have a long history of not working well in our Jeep engines. A Bosch engineer/Jeep owner opined years ago he thought it was probably caused by Bosch not having nearly as many different heat ranges available in their line of spark plugs as do larger plug manufacturers like NGK, Autolite, Champion, etc.
 

Gollywomper

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Yes those will work without problem. Their only drawback is limited life, especially on newer 4.0 engines with the waste-spark ignition system (coil rail ignition) that fires each plug twice as often which results in half the life for the spark plugs.

If you go with double-platinum plugs like Autolite's APP-985 or Champion's 7412 you'll get 100k miles of "NEVER HAD A PROBLEM" instead of 20-25k. With Autolite's iridium XP-985 you'll get 200k miles of "NEVER HAD A PROBLEM". Personally I've been running the XP-985 since probably 2003 or 2004.

Incidentally, Bosch spark plugs have a long history of not working well in our Jeep engines. A Bosch engineer/Jeep owner opined years ago he thought it was probably caused by Bosch not having nearly as many different heat ranges available in their line of spark plugs as do larger plug manufacturers like NGK, Autolite, Champion, etc.
Any reason to run the XPs in my 98 4cyl?
One of the only maintenance things I have not done since I bought my Jeep 3 years ago was simple tune up as everything looked fresh. Plugs, cap and rotor are on my todo list.
 

Jerry Bransford

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Any reason to run the XPs in my 98 4cyl?
Their fine wire technology is like what's in the platinums too, it helps the plugs fire more consistently in difficult combustion conditions. The benefit the iridiums have over the platinums is about double the life which means they're good for something like 200k miles. The guy there I know who is the tech manager and trainer at Fram/Autolite had his car's iridium plugs pulled at 200k miles by their lab. The electron scanning microscope in the lab detected zero wear on the electrodes.
 

Jerry Bransford

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Yeah.

You can check the codes by turning ignition on off on off on quickly. They will display in the odometer.
Yes, turn the ignition switch On-Off-On three times within five seconds then leave it in the On position. Give the diagnostics routine several seconds to complete and then any stored diagnostic trouble codes will start displaying in the odometer display.
 
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A

ALScott

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Yes, turn the ignition switch On-Off-On three times within five seconds then leave it in the On position. Give the diagnostics routine several seconds to complete and then any stored diagnostic trouble codes will start displaying in the odometer display.
Thanks for that! I had no idea. I did it and it only displayed "done" and then flipped back to the odometer.