attached is fail sheet with numbers.
HC GPM 1.88 limit is 1.2
NOx GPM 2.91 limit is 2.5
passed everything else

did a bunch of work on it last (early) fall including....

new plenum gasket and everything involved in that kit (exhaust/intake gaskets, bolts etc)
wires
plugs
cap/rotor
o2 sensors
timing chain/sprockets
timing chain cover gasket
water pump & gasket
air filter

also did the clutch while i was replacing the freeze plugs behind the engine block that had rotted out. (ugh)

it's a 1500 5.2L
truck has 240k on it now. i got it with 200k about 5 years ago.
its always seemed sluggish (plenum didnt change that), but starts/runs fine. get 13.6mpg daily, touch under 16 if i'm exclusively highway.
check engine lights pretty much been on since i got it, and i passed at least 2 other inspections just by having the code deleted before going to emissions or unplugging the battery to reset the ecu.
the CEL reads an o2 code, but like i said i've replaced them and it still comes back on. and seems to run fine. not the smartest, i know. is what it is now.

so....any insight into what the numbers mean and where i should start to fix it?

thanks!

 

I would replace the catalytic convertor.

 

Yep, that would be a good start.

What brand O2 sensors did you get? Numbers indicate you are running a bit rich?

 

pretty sure it was NGK, but not 100%. got it from napa, and it wasn't their cheapest one.

is welding a new CAT in a must, or could i get away with some U clamps and still pass?

i'm a carpenter and use my truck for work every day. taking it to a shop during a weekday, paying for the labor, and then being without my truck/tools costs a ridiculous amount more than doing it in my driveway on a saturday, but unfortunately i don't know how to weld or have the tools for it.

 

Get a magnaflow high-flow direct fit cat. Bolts to the exhaust manifolds, and you will have to clamp it, or get it welded on the other end. If your truck is 94-99, the cat has two pipes coming in to it, and adapting something without welding is not really possible.

 

it's a '98

looks like the magnaflow direct fit one is $450

ouch. i imagine most shops would quote me above that though, plus the cost of me taking a couple hours off to have it done.

 

You can find them a LOT cheaper than that. Under 200 if you look. Check Rock Auto. They generally have good prices.

 

thanks for all the help.

don't see any magnaflows for under $270 anywhere.

there's some different 'exact fit' and 'direct fit' brands at rock bottom for under $200
not sure what the difference is, or if its even worth it for a truck with 240k that i just need to keep rolling along.

one more recommendation?

http://www.rockauto.com/catalog/x,ca...,parttype,5808

 

Try running some Seafoam thru the system. Had a friend dig an old Windstar out of his back yard and it failed miserably and he didn't want to throw a ton of money into it. I told him to try some in the tank and he went to his sisters on the weekend (2hours each way) and had it retested Monday morning and it passed with flying colors. With the size of our Ram tanks I would add 2 cans in.

 

did seafoam the fall before last. in gas tank and vacuum lines. it smoked pretty good, but i didn't notice much difference in performance or how it ran afterwards.

any suggestion on a cat from rock auto? don't want to get the wrong one or something that won't essentially be plug-and-play with a snug fit.