97 5.7l runs a little rough on idle

[houndog3]

I just finished replacing the intake gasket!! Thank you all for you support!! It went pretty well..This is my new problem..I will give you a little history before i tore it apart.It ran fine!! idle smooth,ran good,i would get a o2 sensor code on bank 1 before the cat..i would reset it or it would go away..it ran fine..Now after i did the intake gasket it idles a little rough,it gets better about 50% after it gets up to temp...i did it with the old distrbuter,i replaced the distributer and cap and took it to my small local garage and timed it... the timing is rite on...the guy that timed it used a snap on computer,and he said i had 2 codes saying both of my o2 sensors b4 the cat were bad...do you guys think this is possible why the truck idles a little rough now..i know i should replaace them..but can this cause this issue just like that.. after major pepair is done. It took me a week to fix the truck i had the battery disconnected,did the computer do a major dump??does it need to relearn anything over again????I know it could be a million things.Im just looking for small mircle of somebody seeing this isssue before....thx for all your help jeff

[jamesslcx]

houndog3 how far have you driven it since you did the work? The computer will have to relearn, anyway you probably will have to replace the 02 sensors to get it to run like you want.

[j cAT]

Originally Posted by houndog3

I just finished replacing the intake gasket!! Thank you all for you support!! It went pretty well..This is my new problem..I will give you a little history before i tore it apart.It ran fine!! idle smooth,ran good,i would get a o2 sensor code on bank 1 before the cat..i would reset it or it would go away..it ran fine..Now after i did the intake gasket it idles a little rough,it gets better about 50% after it gets up to temp...i did it with the old distrbuter,i replaced the distributer and cap and took it to my small local garage and timed it... the timing is rite on...the guy that timed it used a snap on computer,and he said i had 2 codes saying both of my o2 sensors b4 the cat were bad...do you guys think this is possible why the truck idles a little rough now..i know i should replaace them..but can this cause this issue just like that.. after major pepair is done. It took me a week to fix the truck i had the battery disconnected,did the computer do a major dump??does it need to relearn anything over again????I know it could be a million things.Im just looking for small mircle of somebody seeing this isssue before....thx for all your help jeff

with the battery removed it will take a little bit running to ge the computer operating correctly.

O2 sensors under a perfect operating world will work for about 150,ooomi.

in the real world about 100,ooomi. upstream sensors exposed to contamination fron failed gaskets/coolant fail much faster.

when the O2 sensor [s] fail the cat converters/ MPG goes down.

[houndog3]

james...Iv only got maybe 20miles on it tops!! I will give it some more time...i only drive it 10miles s day to work.. i will plan on replacing those o2 sensors.!!! I put in a set of bosch o2 sensors 2 yrs ago..is there a better brand to put in,and a cheap website to buy them...they cost around 70.00 a pcs...thx for your help sir!!!!

[jamesslcx]

houndog3, that's a good plan. Yea those parts houses thik a lot of those 02 sensors don't they? Bosch is good, maybe after you drive it some and with any luck those you got in there will be ok. shame they are only 2 years old. Good luck.

[777stickman]

Most o2 sensor codes do not say to replace them until extensive test are done. Things like vacuum leaks, injector issues, fuel pressure issues, etc, etc. Many times the o2 code is telling you that something else is going on that's not right. In my opinion the direct replacement AC-Delco sensors are the best way to go.

http://www.gmpartsdirect.com/ for prices.

[j cAT]

Originally Posted by houndog3

james...Iv only got maybe 20miles on it tops!! I will give it some more time...i only drive it 10miles s day to work.. i will plan on replacing those o2 sensors.!!! I put in a set of bosch o2 sensors 2 yrs ago..is there a better brand to put in,and a cheap website to buy them...they cost around 70.00 a pcs...thx for your help sir!!!!

what are the O2 sensor codes ?

the sensors you installed , did they have the correct connectors ?

[houndog3]

yes they do jcat...i was afraid of the universal sensors

[houndog3]

opps sry jcat....p0153, p0133 were the codes

[j cAT]

Originally Posted by houndog3

opps sry jcat....p0153, p0133 were the codes

these codes are the same failure for both ...bank 1-2 sensor 1 , slow response from both sensors...check the O2 heater fuse. this is because the O2 sensor is taking too long to start switching which is a low amplitude ac voltage that the computer is looking for. heater circuit is most likely bad. if all the fuses are good then wiring and grounds..

[777stickman]

The "heater" fuse referred to is the "ENG 1" fuse, 20a, in the under hood fuse panel.

With both of those codes showing, it's a strong possibility that both sensors are contaminated and need to be replaced.

Some areas of contamination are:

1. Wrong RTV sealant.
2. Coolant in the combustion chambers.
3. High oil consumption.
4. Contaminated fuel.

[houndog3]

ok stickman... i check the fuse under the hood,it was good...i do know the head gaskets are good,i do use some oil(1/2 qt to 3k miles ish) but i do put in some lucus fuel treatment in now and then (every 10 tank ish ) may be thats my fuel contamination???

ps I love that #3 car!!! thats bad ass!!!

[j cAT]

Originally Posted by houndog3

ok stickman... i check the fuse under the hood,it was good...i do know the head gaskets are good,i do use some oil(1/2 qt to 3k miles ish) but i do put in some lucus fuel treatment in now and then (every 10 tank ish ) may be thats my fuel contamination???

ps I love that #3 car!!! thats bad ass!!!

see if you have 12 volts at the heater connection at the O2 sensors.

could be bad wiring in the12volts/ ground of this circuit.

[777stickman]

Originally Posted by j cAT

see if you have 12 volts at the heater connection at the O2 sensors.

could be bad wiring in the12volts/ ground of this circuit.

Pink wire is the 12v signal with the key in the "run" position and black is the ground.