YACT: Spark Plug Question...

Scarpozzi

Lifer
Jun 13, 2000
26,391
1,780
126
I have a 99 Jeep Cherokee that I've posted about on here. I decided that since it has around 40,000 miles on it now that it was time to replace the spark plugs. I hit AutoZone yesterday and of course they were out of the standard Champion plugs that fit my Jeep...but they had some Champion Truck Plugs. So they're a little different(thicker porcelin, but I got em spaced and then installed them. I had cleaned my throttle body assembly with some cleaner and a toothbrush so when I finally started the Jeep up it idled rough for a minute or two to burn the cleaner. My question is that in the case that a plug wasn't firing right, how could I tell? I can imagine the idle would be pretty rough, but I've never heard an engine that didn't have all cylinders firing.
 

notfred

Lifer
Feb 12, 2001
38,241
4
0
The check engine light would come on and you'd get a "running rich" error code.

Edit: if you want to see what it's like, go pull one of the spark plug wires and start it up. It won't break anything, just put the wire back on before you drive it.
 

Scarpozzi

Lifer
Jun 13, 2000
26,391
1,780
126
Originally posted by: notfred
The check engine light would come on and you'd get a "running rich" error code.

Edit: if you want to see what it's like, go pull one of the spark plug wires and start it up. It won't break anything, just put the wire back on before you drive it.
That's pretty much what I thought. I checked the exhaust and listened for any rough engine noise through the muffler.... It seemed as though the idle cleared up after it ran a min or so... I just hope all the stuff I did today fixed my idle problems in cold weather.... My idle air controller wasn't working right so I decided to clean the throttle body assembly with a toothbrush and cleaner before I go replacing parts that all cost around $50-75.