[bazook]

I have a x90 g16b in my sierra that once its warm it goes from 1000 rpm down to nearly staling then goes back up to 1000rpm and back down again...

Could this be the airflow meter doing this or is it something else, by the its running the standard computer.

[royce]

check engine light working but not on?

first step like always, check for air leaks, check the adjustment of the tps, clean the air flow meter with electrical clean

mine has done that before but its only ever been idle high when you take your foot off the throttle then drop to idle after a few seconds

also try unplugging the IAC, will tell if its the ecu upping the speed or something else

[kenn]

Check O2 sensor plug also..

[bazook]

iac was the first to come off might see if the engine light shows something

[steak_knife]

how many wire O2 is yours??

[bazook]

4 sir steaky

[bazook]

I think

[steak_knife]

Pull the code's, if any & we can go from there..

wish I had a tech 2 live data is friggin awesome..

[stockman]

Is there a 4 wire o2? Or 1 or 2?

[Damo]

If it's an X-90 g16 it should be a 4 wire O2.

[steak_knife]

stockman wrote:

Is there a 4 wire o2? Or 1 or 2?

1 & 4, the 4 wire has a heater for cold start's..

1 has one wire...

[losfer]

forget the o2 sensor , do what royce said