Hey guys, have had my check engine light on for a while, usual crap with the emissions.

Ok, I have a magna flow cat, and I will be checking the EGR valve tomorrow, and getting both new O2 sensors.

Anything else I am missing? I'd hate to put this all on and in 10,000 or 50,000 miles have the same crap happen because something was not right and fouled my o2 sensors and cat again.

Anything I can do after it's all put on to make sure it's 100% fine?

 

Year, engine, etc. PLEASE update your profile specs, it helps alot.
You said Check engine light, so it is NOT a renix. Therefore, you do not have an EGR valve.
2 oxygen sensors should do it, whens the last time its had a tuneup too?

 

well before you buy the 02 sensors,your should carfully clean them. and try readjusting them. i did to mine.. worked fine..but if you want new, go for it, more money than im willing to spend. and just make sure you do routine checks to make sure they dont loosen or get to dirty

 

Ah sorry, it's a 2000 XJ with 93,xxx.

I'll update jeztz.

 

k.. If its a 2000 then you do not have an EGR valve, so you dont have to worry about that... I think some (california) cherokees came with like 4 oxygen sensors, so I would crawl under there just to be sure.

 

Ah excellent, it came from Chicago, and I can only find two o2 sensors.

Anything I should check replace while I'm at it?

 

If you have the time/money (and a garage, since its cold here) it would pry be a good time to do a tuneup if you havent done one lately.
Plugs, wires, cap and rotor. Alot of people say just to stick with the Champion spark plugs.

 

Ah, just did the plugs with Champion, and the boots(waste of money).

I asked at autozone, and they said I wouldn't need wires? I'll read about the cap and rotor too, haven't heard about those yet.

I wish I knew more about vehicles...

 

wait, Im a dumbass... I dont think 2000s have a cap or rotor lol.
Pry why they told you you wouldnt need wires either, the 2000 is coil on plug, isnt it? (no wires)
Yup, looked it up. Its distributor-less ignition.. You dont have to worry about cap/rotor/wires...

where in Michigan?

 

yes 00s are COP ignition. there's still wires but they're not spark plug wires...they're signal/power wires from the PCM that fire coils.

 

I'm curious as to what codes are/were stored.

 

Cool, yeah my dad said there was no rotor or cap at all either, as well as no wires. Saves me time and money.

I'm in mid-Michigan, about 20min west of Flint.

As for the codes that were stores, I know one was P0420 and that was the earlier code at the beginning of my problems.

Later it was scanned again and the was with my father when it was scanned and I guess the code said it was the catalytic convertor.

I got both new o2 Sensors tonight, and my Magnaflow convertor in the mail yesterday, so I suppose I am all set! No more 12mpg.

 

in my repair manual it says P0420 means "Catalyst efficiency below required level"

 

Yep.

Checked everything on the list, and pretty sure the cat was bad, mileage whent from 20mpg, to 17mpg, and then 12mpg.

Also read online it could be the o2 sensor(the rear one), but mileage went down really bad with from what I understand is controlled by the first one possibly being bad and fouling out the cat.

That may sound completley ignorant to some of you, but I do not know much about auto mechanics, and I am sick of 12mpg when i used to get 20.

Just going to spend the money and replace everything while I've got it.


I have also read about some engines buring oil, or something to that degree that also can plug up a catalytic convertor. Whatever that is, how do I check to make sure that isn't happening?

 

I doubt your 2000 is burning oil, unless you beat the hell out of it.
Sounds like your first oxygen sensor was bad and caused it to run rich, eventually killing your cat.

Im about 8 Miles west of Midland...