O2 sensors 1986 442

[Blues Pwr]

Hi, I have a 1986 442 W/307 9 code engine W/computer controled Q-Jet carb all stock, still has original exhust manifolds and smog pump all still hooked up, it has 142,000 mi.
It still has factory Cat. Converter, are there any ways to use a by-pass pipe or modify this so its just a straight through unit.

I need to know how many O2 sensors there are on this model and their locations.

Also best place to buy them, I checked on E-Bay and prices run from a low of $6.99 + $2.52 s/h for a no-name sensor to $44.79 w/free shipping for a NKT.

Also some state 1 wire and some appear to have 2 ?

Average price seems to be around $17.00 w/free shipping.

Some say upstream and some say front/rear so are they both the same ?

I really don't want a cheap chinese piece of crap, but I don't want to throw away money on a name brand if they are all about the same quality wise.

Thanks in advance for any and all info provided, Blues Pwr / Curt........

[88hurstolds]

There is one O2 sensor on the passengers side manifold.
It's a one wire O2 sensor.
You get what you pay for when it comes with 02 sensors... and you will be sorry if you go with anything else besides AC Delco.
I've seen many instances of top dollar brand O2 sensors failing to provide the correct output for these cars and causing headaches.
Get the correct AC Delco O2 sensor from rockauto.com, AFS21 is only $14.32.
As for the CAT, check with your local state laws, it's most likely illegal and no shop will touch removing it or build you a "test pipe".
You are pretty much on your own with removing and replacing with a pipe because no one sells a CAT delete pipe.


If you are having performance issues, these cars are very sensitive to EGR.
Get a new one and clean out all the EGR passages in the intake below the carb and on the EGR pad.

Also, the CAT can be clogged so it's always good to replace that as well.

[Blues Pwr]

Thanks for the quick reply and the info.

I have the O2 on its way from Rock auto which with shipping is still cheaper than a Bosch locally at Auto Zone.

Looked at the EGR there seems to be plenty to choose from, actually too many, any recomendations on that and for the Cat.

In Florida there is no inspections and emission testing.
I am almost certain the cat. is clogged the first 139,000 mi. were put on by the first and only other owner/driver a woman who was in her early 30's when she bought it new.

[88hurstolds]

Walker makes a CAT, get an AC Delco EGR valve where possible.

[Blues Pwr]

Thank You Both, I appreciate the help.