# 04 GTO running rough...maybe O2 sensors?



## taylorjones_11 (Jun 19, 2013)

This topic might have been discussed before but I never found something exactly similar to my situation so i'm starting a new one. I have recently been having trouble with my goat running very rough and being down on power, but the interesting thing is its only sometimes. Some times i'll start the car and it idles below 500rpms and very rich, smells like fuel from exhaust, just idling about 1.7-2 gal/hr is registering in the dash. When I drive it just seems to be dumping a huge amount of fuel into the engine. Mileage is in the single digits in town, and sometimes won't run over 30-40. If I clutch it and rev it up it will rev fine, but under a load it won't run hardly at all. Then all the sudden like someone flipping a switch on, car runs perfect. Actually almost seems to have more power than ever. Fuel milage comes back to normal and everything. The car has done something like this before but its been 3 or 4 months back. IT happened for two days, then quit and check engine light went off. But now for about 4 or 5 days consistently it has had this problem every time I've started it up. Let me know what you guys think. I've embedded a video below of my experience on the highway today.






04 GTO Occasionally running rough - YouTube


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## svede1212 (Nov 1, 2005)

A scan while running would reveal O2 issues as your fuel trims would go wonky.


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## taylorjones_11 (Jun 19, 2013)

*Happened before*

I'll see if I can get a scanner on it while its running. The problem is that its such a sporadic thing that I hate to borrow one and have someone help me with the problem and then the car perform like nothing is wrong. I am planning on pulling the history to see what it says. In the past its done something similar to this and I pulled a code that said bank two sensor 1 O2 sensor had no activity, but the issue cleared up after a day so I didn't think anything of it. I'll reply back with what the code reader says.


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## taylorjones_11 (Jun 19, 2013)

Okay so I got a scanner tool and received the codes P0154, and P1153. the first one explains there is no activity on bank 2 sensor 1. The second code calls for heated oxy sensor for bank 2 sensor 1. I then fired the car up and watched the numbers and looks like whenever the bank 2 sensor 1 drops to no signal, fuel system percentage shoots up dramatically. I'm guessing that an O2 sensor Job should fix my problem, but my only issue with this is that it is so random that it runs like this. Recently it has gotten worse, but Sometimes i'll fire the car up and run it for 20 minutes without any problems, then I'll fire it up again driving it for 5 minutes and it runs terrible.


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## taylorjones_11 (Jun 19, 2013)

Quick update. I pulled the negative batt cable for a while then put it back on and fired it up. I let it Idle for about 10-15 minutes to make sure it was at full operating temp before I took off. Took off and the car pulled like it did a while back when it was healthy. Spun the tires all the way through second gear and chirped in 3rd. Drove it for about 15 miles pretty hard, then came into town and putt around for a while normal driving. Drove perfect smooth Idle, came home let it sit in the driveway for another 5 minutes everything was normal. Fuel consumption was a little on the high side but I figured it was just the computer re-learning. Killed it went inside for about 30 minutes then took off to head to work and car runs like crap, Idles rough, no power, running super rich again, check engine light flashing. I don't get why its so random...


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## svede1212 (Nov 1, 2005)

Random electrical could be one of the grounds although a sensor could still do that too. Check the plug for your O2s. If the connections are good I'd try the sensor.


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## taylorjones_11 (Jun 19, 2013)

I ordered new sensors and new extensions just to weed out any problem I might have, and while waiting for them to come in my car all the sudden clears up and check engine light went off. It's been driving normal for 3 days now, no problems like I had in the past threads. Everything is good, car is running just like it normally does. Crappy thing is that now I can't tell if changing these sensors does any good or not. I'll most likely wait until it happens again before I do anything to it. Who knows though that could be another 6-8 months


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## taylorjones_11 (Jun 19, 2013)

o2 sensors are in, and car seems to be running good now. Gonna keep an eye on it before I install the new extensions. If it stays good, I may resell, or try to return the extensions. I'll keep everyone updated on how its running. So far so good!


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## silversport (Mar 23, 2007)

hopefully that fixed you up...good to hear.

Bill


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