mike c.

iTrader: (1)

my 2001 trans am has heads, cam and all the boltons. after the head and cam swap my car will idle great but after i floor the gas pedal then let off the car's idle will drop to 400 to 450 rpm's,search for an idle for 5 seconds or so,then return to normal.NOW i hade the car customed tuned at speed inc.and the car will still do this after tunning. the thr.body is drilled to 1/8th can any one help? my car runs faster then ever after the tunning, but i still have this problem and i dont want to make another 5hr trip back to speed inc. thanks , mike c.

mmiller

iTrader: (1)

Drill out the TB hole to around 13/64's. Is your computer tuning done with LS1 Edit? If so, set your idle around 875 RPM and drilling the TB hole bigger won't affect the idle.

mike c.

iTrader: (1)

i redrilled the hole to 3/16 and there is still the idle problem and now my ses light came back on. yes speed inc did use ls1 edit. any help is great i don't want to drive 5,hrs back to speed inc.

mmiller

iTrader: (1)

Mike, a 3/16" diameter hole isn't going to do anything. Keep going larger up to at least 13/64" like I posted earlier, maybe even larger. Go in slow increments and be patient. The reason your car is surging is due to lack of air at idle. The only way to fix the problem is to increase the size of the TB hole. BTW, what is the timing set at at idle?

mike c.

iTrader: (1)

i don't know what the timing is set at. speed inc told me they dont give the cars too much timing, or over time them because it dont give the cars hardley anymore power. my car will idle fine it's when i race it then let off the gas i start to have this problem. if i'm sitting at a stop light and the car is idling fine at 850rpm's if i give the car a little gas to pull forword alittle, the problem starts again. thanks for the help this far,im going to go drill the tbody bigger right now.

98TAauto

iTrader: (2)

Before you drill to much log your IAC's with the engine warm on Atap. They should be in the 20-40 range for best idle. Mines around 30, but sometimes its up around 50 for some weird reason.

I still get a little surge, but its no where near as bad when my IAC's were 70-90 <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

some guys add timing at low rpms to help with this also, but im not 100% certain how they do it. I believe they go to BASE Spark in drive and park on edit and edit the 800-1200 range

mike c.

iTrader: (1)

i have drilled the t,body to 13/64 and i still am having this problem. after driving the car when i turn it off and re start it, it searches for the idle and sometimes stalls. my ses light is on also. how much bigger am i havivg to drill,i know guys with head and cam with the stock hole? i hope i dont have to buy an auto tap and ls1 edit, that would make my speed inc trip a wast of time and money.