I pulled the plugs in my 99 Cherokee and put in new ones. Had champion plugs. Put in ngk. New cap rotor and wires too. Plugs that were pulled were in bad shape. I checked gap and was at .065/.07. I gapped new at .035. I'm not a mechanic so took me a good 4 hrs got all. When done, fired up. Runs worse now than before!!! Actually ran fine before but I knew it needed new plugs. Spits and sputters. CEL on! What the crap?! Suggestions?

 

Got a wire or two crossed?

 

x2 check to make sure you got all your wires going back to the right plugs.

 

I see you didn't change the spark plug wires but maybe the connection between your plugs and wires are not solid.

This may sound odd but it just happened to me. Look down into your spark plug wells. Do you see any arching? Do hear a ticking sound? Sometimes the spark plug boots can be just a tad too long...just enough to push the connection slightly apart. This will cause your jeep to start rough, idle rough, start then die, ect,

My fix was to trim just about 1/8th of a inch off the boots and it fixed the problem.

 

this may help ya out...

 

It may be a little late now, but you always change only one plug and /or wire at a time. That way you don't get them mixed up.

Also, if you used Platinum plugs, they come pre-gapped. .035 may be too close.

The plug boots must snap firmly onto the plug, and they must snap into place on the cap for a positive connection.

 

That's a good illustration of the location of the respective wire locations on the cap. Pic needs to be a bit larger however.

 

Got it! Two wires crossed! Thx for help everybody!

 

Here Ken:

 

Not good. That shows #1 at the 6 o'clock position, not at the 5 o'clock position, like Ant's pic shows (and in real life).

 

Can someone fix that for us?

 

It worked!

 

Thanks. You bet it did. Hopefully I'm the first to steal it. Before CCKen anyway.......

 

Steal away. Sometimes my copy/paste of images and pics don't work.

 

Stolen, saved, and forwarded to those who will appreciate it and share it. Thanks again.