LS1WS6dreamer

iTrader: (1)

Well here is the story. Car idles high like 1200 rpm's right after I let off the gas, drops down to about 900rpms after 15-20secs of not giving it any gas.
Did this before the new TB I put on yesterday. Now it idles barely higher like maybe 100rpms I guess. Also noticed that I have a slight RPM surge hard to guess, but feels like a 50-100rpm increase, up and down, up and down, you can feel it when the car is sitting still. I am guessing I have a vaccuum leak for the surging, but the high idle is just starting to **** me off. Car runs fine other than that. No surging at cruising speeds.

any ideas?

more info towards the bottom

kinglt-1

iTrader: (26)

my silverado with the 5.3 is doing this with a ported tb I installed. Thing is i put the stock one back on and the problem went away. A guy suggested cleaning the maf... not sure if it will help, just thought that I would share that info.

LS1WS6dreamer

iTrader: (1)

Yeah I might try cleaning the MAFS. It idled high before I put the different TB on there. And yesterday I didn't even notice it having the RPM, idle surge. Its one of those annoying little things I guess.

MjMaro

iTrader: (11)

Sounds like a vacuum leak to me if it takes a long time to drop RPMS or if it holds a higher rpm than desired. I would go over all hoses, connection points, and seals with a fine toothed comb. With your mods doesn't seem any reason the car shouldn't idle around 650-700 rpm once all is said and done. The IAC may be to blame, or a vacuum leak somewhere. Take your time and go through everything. Was there a point where it started doing it after a certain mod or something? It may give you a clue where to start. My car is idling at 800 and I'm not satisfied with it so i am going through much of the same process. It can be frustrating but it is worth it once everything is working properly. Good luck.

LS1WS6dreamer

iTrader: (1)

No mod that seemed to kick it off. In fact my PCV hose was ripped and all screwed up and I fixed that and it still did it. Is it possible to spray WD40 or something to check for a leak. Or is that a bad idea? It seemed to be doing it worse this morning when it was colder outside. Now its not doing the idle surge thing I spoke of earlier. I am gonna check it out when I get a little more time.

LS1WS6dreamer

iTrader: (1)

OK here is somewhat of an update. Car seems to idle around 900rpms when its cold. Drive it for a while it starts doing the high idle thing. Between 1400rpms-1100rpms. Also when its idling high I can switch my ac on and its fine. This also works with the intermittent surging(the up and down, up and down thing). If its idling up and down I can also unplug the IACV and it stops, plug it back in and instantly does it again. The idle seems to also drop when I am sitting still with my foot on the brake. Going down the road cruising at say 1100rpms and push my foot in on the clutch, bam the idle goes up.

Maybe all this badly worded info will get me some more ideas of what to check. I plan on cleaning the IACV. Prolly get the codes ran and see if something pops up. My !AIR gives me a CEL all the time so I have no way of knowing. Other than that the car is running awesome.