need help badly

[Howling Mad]

So I started my car today, just put in a built motor, and the O2s are going f'ing nuts at idle. Never above 300 and will drop down to damn near 0. Also the car idles around 975-1000 then drops to 600-700 and tries to stall then pics up. This does not happen at the same time that the O2s drop. Help please.

 

[Boost231]

Did you try a new 02

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[Howling Mad]

I have one but didn't have time to run to the house and grab it. Just don't want to get my hopes up that its just an o2 sensor and then still have the same problem.

 

[Boost231]

I would change the 02 as that could throw the car way out of wack, check tps and iac as well

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[Howling Mad]

Tps is .42
Iac is 29
New o2 and its showing around 390 at idle.

 

[Howling Mad]

Also checked grounds, and vacuum lines.

 

[earlbrown]

Define ''built motor''.

 

[Howling Mad]

Forged crank, scat rods, wisco (spelling) pistons, champion ported iron heads, 206/212 roller cam, billet mains(#2&3), 60 lb injectors. Any more info needed?

 

[1fastcobra]

Also checked grounds, and vacuum lines.

Intercooler hose clamps
Blm's & int #'s

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[Howling Mad]

Blm was 128