Running rough at idle....HELP?

[dssking]

Gentlemen,

So I put the stock o2 sensor back in, but it still runs rough....haven't changed the MAF yet.
I'm told that most GN's are like this ?? Once warm, it idles great.

Can anyone comment? This can't be the case.... I really need a scanmaster which I hope to find
at Carlisle this weekend...............

When I say rough, it stalled on me 3 times getting it onto my lift in the garage............

HELP!!

 

[mtocrs1]

Without a diagnostic tool we are all just guessing. It should not die. Allot of these cars hunt at idle but it's not a rough running condition that allows the car to die. Have you tried unplugging the MAF sensor. Does it run better unplugged? What about with the O2 unplugged?


Sent from my iPhone using Tapatalk

 

[dssking]

I'll try unplugging the MAF then the o2........will report bAck

 

[mikestertwo]

What chip are you running. If it's the stock chip get rid of it and get a Turbotweak chip. Unplugging the O2 sensor will buy you nothing.

 

[dssking]

Yup, stock chip. I'll order the TT 5.7 tomorrow morning. Trouble is that it's a 7 day programming time and shipping. (In Markham)....north of Toronto. Nothing's easy for us Canadians.

 

[mtocrs1]

Unplugging the O2 will flatline the reading to around 700. It makes a difference.


Sent from my iPhone using Tapatalk

 

[mikestertwo]

Unplugging the O2 will flatline the reading to around 700. It makes a difference.
Sent from my iPhone using Tapatalk

It still won't tell him what's wrong.

 

[mtocrs1]

It still won't tell him what's wrong.

Wouldn't that tell us if the O2 is switching?
O2 unplugged, car smooths out= sensor is switching and the issue is in the air metering.
O2 unplugged no change = issue with O2 or fueling.
Is this not correct?


Sent from my iPhone using Tapatalk

 

[TurboBuRick]

The o2 sensor really has nothing to do with cold idle. It does not effect the tune until the system goes into closed loop.

The most common thing that can effect cold idle is coolant temp sensor. If its not sending the correct reading, it can mess with fueling.

 

[Turbo6inKY]

The o2 sensor really has nothing to do with cold idle. It does not effect the tune until the system goes into closed loop.

The most common thing that can effect cold idle is coolant temp sensor. If its not sending the correct reading, it can mess with fueling.

Or a massive vacuum leak.

 

[mtocrs1]

The o2 sensor really has nothing to do with cold idle. It does not effect the tune until the system goes into closed loop.

The most common thing that can effect cold idle is coolant temp sensor. If its not sending the correct reading, it can mess with fueling.

I missed that it was only when cold. Good call


Sent from my iPhone using Tapatalk

 

[Frederickdav]

I agree with Mikester my 87T would not idle worth a hoot. It didn't matter what I changed or how much money I threw at it. Until I changed the chip! Since then it's been a joy to drive, even when cold. In fact it kind of scares me because when I pull up to a stop, when it used to stall, it idles so smooth I look for idiot lights.