I recently entered the world of jeeps with an 01 Cherokee classic 75,000 mi.
1. about a week ago it gave me a #3 misfire code on the ride home from work. Hasnt done it since. It seems like everyone here suggests copper spark plugs, but the parts store wanted to sell me platinum. Does it make a difference? Still rocking original plugs, i think.
2. The bracket that holds the tail pipe and heat shield on has rusted out and the tail pipe dangles. Heat shield still in good shape. Do the 2 bolts that hold this in place attach to anything other than the frame/ piece of metal in the tube of the frame which has bolts mounted on it? I don't want to crank those off and disconnect something else unknowingly.
Thank you, thank you for any info.

 

With the plugs it does make a difference. Just tell them that you want NGK copper plugs. Make sure to gap them at .035. They just want to sale you the expensive plugs which you don't need. As for your second question I really couldn't say.

 

thanks for the help on the plugs!

 

The plugs should be changed every 30,000 miles. Go with the plugs that are recommend on the sticker under the hood. They are NGK but the number I can not bring to mind.

 

I have an 01 Sport, less mileage exactly the same error code and code. It happened once, I cleared it and never saw it again.
I bought a cheapie bluetotth obd dongle and found that I had lots of pending 303s.
So I did a search here and had a list of fixes;
wiring break down
plugs

So with the 2001 it is coil packed and with the NGK plugs seem to be recommeneded by the members. Bought a set of NGK V-powers an stuck them in. The wiring issues that may exist didn't seem to not show on mine.
After the plugs and getting my cheapie dongle OBD reader to work everything is good.

Plugs are cheapie eyes into the engine and mine all had nice pinkish/grey deposits, were worn and used up but showed no other signs of problems.

So for your 303 I would change the plugs and check them for any problems!