For the past few days, my XJ has been idling rough for about 15-30 seconds when I start it. After that, everything's fine.

Today my check engine light went on and it threw the P0303 error code, meaning that cylinder #3 has misfired. I assume that the rough idling is a symptom of this. I've read that there's a fix for it, but is it fine to drive for now?

 

Yeah its fine its just heat soak most 97-01 xjs and zjs do that my 2000 does all time

 

what year is your rig?

 

Its a 2001.

 

Been there, my 01 is really bad with it on short trips and startup soon after.

 

It can be a great many things. Seach the sight, read, and do thethings recommended. This topic has a wealth of usable info. It is not a simple diagnosis. Misfire and idle issues can range from spark plugs, to coil packs, to injectors,to cracked heads or bad rings. You def. need to see if you have 0331 heads, the manufacture date, and more.

Searching and reading will do you a lot better than accepting any two sentence responses here.

 

Did you try the heat shield wrap fix?

 

Getting this as well. I have the write up on the TSB but does anyone have the diagram for it? Can you still get this part from the dealer?

 

No, too many other projects right now, with winter coming it shouldn't be.much of.an issue

 

I think you can just get the heat shield wrap from autozone or wherever. I would also like to see a diagram, as I have no idea what I'm looking at when I open up that hood.

 

I used to get the same thing. I finally swapped the 784 injectors in, and now it stopped; happens ever so rarely though. On the off chance it does occur, it clears the extra fuel in the injector so fast, there is no code.

The heat shield would be a great fix if you can't get the 784's. The reason why this misfire happens is because the exhaust manifold heats up the intake manifold, and through contact, heats up the injectors, thus boiling the fuel in the injector.

 

Mine does it with that stupid heat shield not all the time just when we been driving awhile then turn it off to go in a store and jump back In within 15 mins, I try to let it sit for 30 mins and its usually don't do it

 

I had really bad heat soak until I wraped my #3 and #4 injectors on my 01' like this and have never had another heat soak issue. I also replaced the stock cat at the same time.

 

I should have passed on the '01 and gotten a 97 or something.

Now I'm all paranoid about the cracked head too.

 

I have the 703 injectors. Think they would help as much as yours?