logikf1ve Posted March 11, 2006 Report Share Posted March 11, 2006 I posted this over on MM as well. Anyways, ever since I got my '97 LTZ w/ the 3100 V6, it's idled really high when cold (3,000rpm), and slightly lower when warmed up a little bit (1,500rpm). When you start it when it's cold, it'll start out at like 1,200rpm and creep to 3,000rpm. Edit: Ok, still can't figure this thing out. Everything I do makes absolutely no difference. Here is a list of things I've changed: -TPS Sensor (Since it fit the symptoms) -IAC Sensor (Also since it fit the symptoms) -MAP Sensor -Temp. Sensor -PVC Valve (rattled internally) -Hooked up a vaccum gauge, was within specs. I even sprayed starting fluid around the LIM gaskets (which were replaced), and all the visible vaccum lines for added assurance. I have run out of ideas. Is there any chance it could be EGR valve related? Oxygen sensor related? Perhaps even a bad computer? Also, the only way I could get the idle to drop down to somewhat normal was to plug the PVC valve (approx 1,200rpm which is still a little high, but better than 1,500-3,000) However, I'm sure it's not a good idea to plug that. Any help on where to possibly look is appreciated. This newer crap really burns my bottoms. :shock: Quote Link to comment Share on other sites More sharing options...
THe_DeTAiL3R Posted March 12, 2006 Report Share Posted March 12, 2006 My car did this when the vacuum line that connects to the top of the intake (right by the throttlebody) was leaking a little bit. You said you checked your lines but just thought I'd share... Quote Link to comment Share on other sites More sharing options...
ToroToro Posted March 13, 2006 Report Share Posted March 13, 2006 Pull the throttle cable bracket, and check the connection from the PCV valve to the intake. When mine did this, I found that the grommet for that hose was mysteriously missing, and it was sucking a shitload of air through there. I made my own grommet out of some larger vaccuum line, and it works good. Still dont know became of that grommet though. Quote Link to comment Share on other sites More sharing options...
3pt1lumina Posted March 13, 2006 Report Share Posted March 13, 2006 One thing I thought of...when you replaced the IAC, did you put the little gasket back in? First time I ever did it in my 90, I left it out, and before I started the car I was like wtf is this.... then I took it apart again and I was like ohhhh! :oops: Quote Link to comment Share on other sites More sharing options...
logikf1ve Posted March 13, 2006 Author Report Share Posted March 13, 2006 My car did this when the vacuum line that connects to the top of the intake (right by the throttlebody) was leaking a little bit. You said you checked your lines but just thought I'd share... Yup, that one is plugged in tight. I even sprayed it with starting fluid after checking it, no idle change. Pull the throttle cable bracket, and check the connection from the PCV valve to the intake. When mine did this, I found that the grommet for that hose was mysteriously missing, and it was sucking a shitload of air through there. I made my own grommet out of some larger vaccuum line, and it works good. Still dont know became of that grommet though. I think I read that thread. I checked it the other day when I was checking all of the vaccum lines. It has the grommet and I can't hear it sucking any air. One thing I thought of...when you replaced the IAC, did you put the little gasket back in? First time I ever did it in my 90, I left it out, and before I started the car I was like wtf is this.... then I took it apart again and I was like ohhhh! :oops: Yup, I made sure I had the little O-ring on there, same with the TPS. Thanks for the help guys. 8) Keep the suggestions coming, because I've run out of ideas. Quote Link to comment Share on other sites More sharing options...
3pt1lumina Posted March 13, 2006 Report Share Posted March 13, 2006 What about a bad injector or a clogged injector? This is for anyone really... I don't know if this would be a cause here. I also heard that if one of the O-rings around the injectors is deteriorated, it might cause a high idle/miss issue. Don't know if that's true but that's what a GM Tech told me. Quote Link to comment Share on other sites More sharing options...
soya_sauce Posted March 13, 2006 Report Share Posted March 13, 2006 well i know you said your intake gaskets were replaced but just out of curiosity how long ago was that?? the 3100 and 3400 engines are absolutely terrible for these gaskets, i've seen them go bad as early as 40,000km from the factory. im wondering if the intake leak is on the rear bank where its hard to reach with starting fluid. the fact that the idle is higher when cold really makes me think the gaskets are leaking. over the weekend i had a 91 lumina come in to the shop for a high idle. when i pulled the codes. i had a IAC error, An EGr Fault, and a Map sensor high voltage code, all 3 codes were caused by the leaking intake gaskets. Quote Link to comment Share on other sites More sharing options...
3pt1lumina Posted March 13, 2006 Report Share Posted March 13, 2006 He just did the intake... the car hasn't been roadtested yet. It's not even 1 mile old... Joe, did the car idle high before the manifold gaskets? Quote Link to comment Share on other sites More sharing options...
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