Jump to content

Bad O2 Sensor Symptoms?


supreme_style21
 Share

Recommended Posts

'94 GP, 3100 engine. Idles fine. When driving, doesn't have the 'get up and go' that it used to.. kinda slugs along when you hit the gas and wanna go somewhere. I'm getting really stupidly bad gas milage.. like 15 mpg highway.. if even that. Transmission fluid/filter changed, new plugs, plug wires, fuel filter, ignition coil, fuel injectors (professionally) cleaned. What the heck could this be?! I was thinking oxygen sensor needs to be changed. Also, what happens when a fuel injector stops functioning?

Link to comment
Share on other sites

Yeah, try the O2 sensor first. If no codes are thrown it could still be a poisoned sensor. Also check the wire from the O2 sensor and make sure it isnt grounded on anything.

Link to comment
Share on other sites

02 sensor sounds like a good place to start. If an injector stops working you would be on 5 cylinders. duh :roll: :wink:

 

Robby

 

well ya.. but what does that feel like?

Link to comment
Share on other sites

sorry, I was in a mood then. It'll run very rough have like no power, the exhaust will smell of gas. It might die sometimes in traffic, idling in gear.

 

Robby

Link to comment
Share on other sites

not to steal your thread but this goes to robby1870, you said it might stall in traffic, with my car, the first time you start it, she'll run awesome. But if you turn it right off and start it again, it will try and stall and run like shit. The RPM'2 will never be stable at idle or anything. Could this be the same problem?

Link to comment
Share on other sites

i had an oxy sensor go bad before....when you start your car go and look at your tailpipe if you see a lot of black smoke its most likely ur o2 sensor or better yet have someone give it a lot of gas and youll see the carbon come out and youll smell it becuase when an o2 sensor goes bad the enegine will run extremly rich.

Link to comment
Share on other sites

sounds like it could be an EGR valve sticking open or closed too, would definately cause a poor idle and sometimes a hard start condition, also fuel economy would go down the crapper.

Link to comment
Share on other sites

I replace the O2 sensor and the CTS on customers cars as a pair. The CTS will hinder gas mileage severly if its bad. The CTS is what tells the ECM how hot the car is running among other things. A bad CTS will not let the ECM go into closed loop operation. In other words, a bad CTS will not tell the ECM how hot the car is, therefore fooling the ECM into thinking it's still running cold and dumping more fuel into the motor in a attempt to get a temp reading to the ECM. If that helps at all? :) :) :)

Link to comment
Share on other sites

Any way that would lead to the car running hotter than usual? It runs around 220.. doesn't take too long to get that hot either. It never ran that hot until recently. Where/What is the CTS? and dare I ask how much that'll cost??

Link to comment
Share on other sites

I replace the O2 sensor and the CTS on customers cars as a pair. The CTS will hinder gas mileage severly if its bad. The CTS is what tells the ECM how hot the car is running among other things. A bad CTS will not let the ECM go into closed loop operation. In other words, a bad CTS will not tell the ECM how hot the car is, therefore fooling the ECM into thinking it's still running cold and dumping more fuel into the motor in a attempt to get a temp reading to the ECM. If that helps at all? :) :) :)

 

That's some good advice.

Here's also a link about other sensors. The O2 sensor is the last authority on trimming the fuel mixture. http://www.asashop.org/autoinc/jan97/techtotech.htm

Link to comment
Share on other sites

I would assume that the CTS = Coolant Temperature Sensor.

 

Oh.. I tend to miss the obvious. Guess that explains the running hot. I replaced that bastard about a year ago.

Link to comment
Share on other sites

  • 9 years later...
not to steal your thread but this goes to robby1870, you said it might stall in traffic, with my car, the first time you start it, she'll run awesome. But if you turn it right off and start it again, it will try and stall and run like shit. The RPM'2 will never be stable at idle or anything. Could this be the same problem?

 

I have a 1994 Firebird V6 and my car does almost the same thing. First trip of the day it runs great. After I park then restart it it runs pretty rough but not as rough as a full-on miss. I don't get a lot of black smoke or anything but I just changed my Plugs, SP Wires, All 3 Coil Packs, and even my Coil Module. The Plugs looked pretty sooty ie carbon fouled. A few years back my car had a over heating problem too. I had the CTS and Thermostat changed then but it still ran sort of hot in summer. My car isn't throwing any codes except for ABS inoperable light and the cruise also stopped working.

 

I'd be grateful for any tips or suggestions on what anybody thinks it might be. Thanks

Link to comment
Share on other sites

You know this is a 10 year old thread on a W-body site right?:shrug:

 

Plenty of F-body sights out there or you can use the WHATEVER section.

 

Winner for the biggest thread bump Ive ever seen:lol:

 

Change your O2 sensor and Cat. converter

Edited by rich_e777
Link to comment
Share on other sites

Actually I didn't but I did look for indicators of those things. I started by doing a google search form bad O2 Sensors Symptoms and a link to this thread popped up fairly high on the list. I didn't see any dates or the posts nor did I see that the original poster wrote that he had solved his problems. So I thought it was a on-going conversation/thread. I mostly jumped in to ask that Randy person if he ever got a resolution to his issues because his symptoms matched mine very closely. Since it is a drive train problem I'm experiencing, and because I know GM used a lot of the same motors and systems in their cars I thought it could hurt to ask. I've also tried several other forums and have found them unresponsive. It wasn't my intention to offend. Thanks for setting me straight. I'm seeking any good responses to my driveability issue. Thanks

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...