Car info: 02 Z28 33K Miles:: Borla CB, Volant CAI, 75MM TB. Everything else is stock.

When I first start my car after it has been hanging around for a while ( like in the mornings before work ), it has a weird idle for about 10 seconds.

The RPM needle will go to 500, then up to 1000, then back down. It is very noticable and you can hear the engine winding up to 1000 and back down to 500. After a few seconds it idles smooth and steady at around 900-1000. It drives fine and there is no smells or smoke, lack of power, leaking fluids, or other signs of damage. Is this normal for an LS1?

Also, if I start it up cold and don't let it warm up, then hit the gas semi-hard ( rev it to 3000s ) it makes a popping noise out the exhaust. I have a Borla CB with the loud plate, everything else is stock. After it warms up for a few seconds everything is fine.

Normal or is something wrong???

 

Mine used to do that. It was hunting trying to find idle, after a few mins it was fine again. I had tinkered with a few tables in the PCM. I was trying to make it idle too low, and not enough air was being delivered (IAC values were tampered with). So because I tampered with some tables and done some mods it caused mine to do the same things. On a stock vehicle this isn't normal.

Has your TB been drilled?

 

http://www.ls1.com/forums/archive/in...p/t-10759.html

 

read......

 

wow that was the totally wrong link im sorry ill find it for ya..

 

I don't think the TB was drilled. Its a BBK 75 or 80MM ( forgot ) bolt on TB. It has the stock MAF sensor.

BTW, i read that link dan posted before I realized he commented its the wrong link

 

the popping is normal on borla exhaust, i have it and i put the plate back on cause i hated that crap.

is your SES light on?

 

I had the same problem last winter. It would only happen if they car was in the shade on extremely cold mornings. The idle would go up and down over and over again till it warmed up and then everything was fine. It finally threw a code the day I went to get my nose fixed after my accident. It had stalled from this, but the code was gone when I got the car back 2 weeks later and it's been running fine since.

 

do you still have the screen in on your maf? Mine started doing similar things when i removed mine...even after it was tuned for it.

 

i still have the screen on my MAF. The SES light, nor any other warning lights are currently present. I am leaning twords this being normal behavior????