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Can a bad O2 sensor cause a misfire code?

Spartanzz

Spartanzz

New member
So i had the ses codes read about a week or two ago and there were two...one for a cylinder 3 misfire and the other for the bank 1 system is too lean...my question is i just bought a new O2 sensor cuz i figure it needs one anyway but can a lazy/old O2 sensor sensing its too lean cause a misfire?
 


ok ill try and give that a shot. But, say the O2 sensor is reading its running to lean all the time is it possible that its trying to put in more fuel all the time to correct it and its just drowning out the spark plug? because i also get pretty bad gas milage so far i just ran it till the display read LOW and thats was at 195 miles or something like that. We thought this could be a possibility.
 
vac leak. Lean bank 1 is almost always a vacuum leak. It would also explain your crappy mileage
 
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hmmmm well i havent had this car very long maby a few weeks now and we are just trying to settel a few things with it and this seems to be the most anoying...i will give swapping the injectors and run up to advanced and have them read the codes but kinda hoping its not an injector because i dont have money to get one lol i have all ready ordered the O2 sensor cuz we had a theory it could be that plus i ordered the zzp supercharger coupler. but if it were a vac leak where is the most typical place to look for the leak?
 


Maybe the leaks leaning out the cylinder causing a miss. Ive not had that But ive heard of people experiancing that. Anywho thats where id start. Id bet 100 dollars the 02's not the issue.
 
Spartanzz said:
if it were a vac leak where is the most typical place to look for the leak?
Click to expand...

don't know what year the car is but there's a vacuum t under the SC snout that tends to split over time. it's part of a vacuum harness that goes from the bbv, fpr, under the snout over to the map. they're like $15 at the GM store.

the #3 misfire might be related but it also could be a plug or wire, something like that.
 
Ok so today I went and bought a can of carb cleaner and started spraying and for a hole in the vaccume line right above the sc. I sprayed there and the engine changed rpm. So what I did was repeat the pipe in the hose and tightened the clamp and sprayed it again. It didn't change rpm after that and I sprayed in more places but didn't hear change. I'm not 100% sure if I did it right so how would I know if the leak was fixed? And for the record its a 1997 grand prix gtp
 


Ok guys so i checked the T under the snout and the hose that connected it to the manifold was loose enough to basically pull off with no force so i got a clamp on that and i actually noticed the engine builds boost faster and it seems to have a bit more power. So now im gunna let the car warm up and stand near the exhaust and listen for the puffs of a misfire that i have. Is there any easier way to check for a misfire?
 
no load idle misfires are common in these dinosour engines. Esp when you start moding. Mine has a mis while idling
 
how old are the plugs and wires?

towers on the coils corroded?

you won't learn much by listening to the exhaust --- you can, most times, tell a lot by looking at the plugs.
 
well i havent pulled the plugs just yet and im not sure how old they are or the wire are. if i can i plan to get a set within the next couple days when i get paid just to be safe but after i fixed the leak the puffing from the misfire is now not as often or at least i haven't head it as often but like i said im gunna try and replace the plug and wires real soon
 


don't know the miles on the car but i doubt it would suffer from wires and plugs. You should be able to get there for less than $50. (i just got a set of delco gtp wires for $14 from rock on clearance pricing).

do yourself a favor ---- keep track of the plugs as they come out. they should, above all, look all close to the same. you'll learn a lot on how your car is running after looking at your plugs.
 
Change your plugs and wires. Cheap maintenance. Then replace that t fitting your put a clamp on. Check the bolts on the sensors on the Throttle body and make sure they are tight and the TB is tight on the SC. If any of your vac. line rubbers look cracked or corroded replace them.

As for the o2 Sensor yes it can cause bad fuel mileage and lean conditions but most of the time bank 1 lean is a vac leak.
 
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