strange problem, first of all i have an after market 4-2-1 header in a 90 ef sedan with d16a6. i CANNOT use the upper o2 bung due to it being too close to the rad fan housing, so im using the lower bung (obd1-2 manifolds).

so anyways its a Bosch 1-wire o2 and when i have it plugged in, i start to bog out when im at like 2000-3000rpms. it wont die, but just sputters a little bit. then when i take i unplug it i dont have these problems anymore.

if anyone had this problem lemme know

 

You have to have it closer... 1-wire O2's are not heated to they will get wrong readings when away from the hotter exhaust. If you just LOVE that "header" then purchase a heated O2 and you can put it in the downstream position. If not you have to put the O2 sensor closer to the head; it's common sense... OR just get the right exhaust manifold for the car.

On second though you never said if you were OBD-1 or OBD-0... If you are OBD-1 then you need a heated O2 sensor because without it you will throw codes...

 

obd-0, and this is far from "common" sense

 

perhaps the best solution here would be to purchase a set of slim fans off ebay for like 40 bux? that way you'd get the clearance you need for the 02 sensor and it wouldn't be jurry rigged

 

haha yea tell me about it i was surprised when i saw it didnt fit. im running without the o2 which is fine. i have a hook up for smog so it doesnt bother me.

im still searching for a "good" 4-2-1 D series header tho, this is some ebay POS but at least its stainless so it looks fancy haha. i want to get a 4-1 but i either need a traction bar or i have to hack the **** out of my cross member.

 

had the same problem a few years back, and i just had another bung welded on the same exhaust runner just in a different position. they have them at napa, and they call the o2 weld nuts. cost about $2.