QuestionI have a 1994 4x4 PU with a 3.0 v6 .
I recently replaced the rusted catalytic converter and adjoining pipe
with brand new ( aftermarket ) parts .
I also then had to change the o2 sensor due to the previous aftermarket sensor
being a larger diameter than the mini style Nissan sensor used in the new pipe .
Soon after this it developed a bad stuttering , driving between 2000 - 3000 rpms , only .
Truck runs fine when cold , but when it warms to normal operating temps I am unable
to maintain a constant speed within that rpm range without severe near driveshaft snapping bucking .
At times when trying to maintain city driving speeds it will surge , or suddenly " clean out "
then resume the stutter , as if a cylinder or two is misfiring .
Under heavy acceleration it pulls ok , which is about the only way to get through the 2-3K stutter range .
Under 2000 rpm and above 3000 engine behaves fine , revs up fine when out of gear etc .
However , I am getting that rotten egg smell from the exhaust , which seems out of place in this day and age .
Any advice you might have will be greatly appreciated .
Pete
AnswerPete,
Make sure you have the proper O2 sensor for your car and that it is installed correctly with conductive paste on the threads. Also, be sure the ground for the exhaust is correctly connected. If the O2 sensor was but connected solder the connection. If it is the correct length and has a factory style plug end make sure it is the same length. Also, look in the relay box under the hood as it has a heater relay for the oxygen sensor. Lastly, make sure you do not have any exhaust leaks as this will cause the problem too. On the exhaust smell it sounds like you need to do a tune on the engine and make sure the injectors are clean as well as the fuel filter. These can cause lean conditions too. Email me back if you need more.
