Another Jimmy Issue

[roldaphat9]

My 2000 Jimmy I noticed has been kind of misfiring, its not huge but its noticable, mainly when I first start it up in the morning. once its warmed up dont notice it hardly at all unless your going up hill and really feeling for it. It hasnt got to the point were it is jerking the truck but I can tell its getting worse. It just threw a code today which was P0420 Catalyst efficiency low-bank 1.

Explanation: the O2 sensors monitor the cat converters ability to store oxygen.
probable cause:
cat converter defective failure possibly due to # 2,3,4.
Engine misfire or running condition.
large vacuum leak.
engine oil leakage into exhaust - valve guide seals, piston rings.

Anybody have any answers for me? I know the cat was replaced not to long ago, so I doubt its the cat. could it just be the misfire that I described above making this trouble code come on? if so why is it misfiring???

 

[Molson02536]

My 2000 Jimmy I noticed has been kind of misfiring, its not huge but its noticable, mainly when I first start it up in the morning. once its warmed up dont notice it hardly at all unless your going up hill and really feeling for it. It hasnt got to the point were it is jerking the truck but I can tell its getting worse. It just threw a code today which was P0420 Catalyst efficiency low-bank 1.

Explanation: the O2 sensors monitor the cat converters ability to store oxygen.
probable cause:
cat converter defective failure possibly due to # 2,3,4.
Engine misfire or running condition.
large vacuum leak.
engine oil leakage into exhaust - valve guide seals, piston rings.

Anybody have any answers for me? I know the cat was replaced not to long ago, so I doubt its the cat. could it just be the misfire that I described above making this trouble code come on? if so why is it misfiring???

Here is a link that should help you with you Jimmy's issues. Good luck and keep us posted. http://members.shaw.ca/betterthanyoutoo/Sticking Poppet.htm