Ok so I'm just now bringing myself to making a topic on this as its starting to show its ugly side again. I've got some weird idling problem going on as far as I can tell. Basically when the car is at normal operating temp and in neutral my idle will sometimes drop below 600 (probably like 580 or so) and everything will feel real rough and the car will Phsycially feel and sound real choppy like it wants to die but does not. This problem has shown its face on several occasions on random days (2 days in a row now) and the car will run crappy. Also want to say when it does do this I also notice that my gas pedal kinda loses its response. I feel like I have to mash down more on it than when its idling right below 1k.

Any information that could possibly point to my problem? The engine is rebuilt with about I would say 10k+ or so miles on it with new plugs/wires/distributor when the engine was rebuilt. I am currently left in a cloud of confusion over it all . I can also add any information I may have left out.

Thanks in advance

-Hazmat

alternator maybe the problem. not getting enough power back. check your voltage

Alternator? Hmm well what would be the best way to go about checking the voltage/power? Sorry, I'm not very technical with stuff like this. I'm guessing probably going to the dealer would be my best bet to get this issue looked over.

This post has been edited by Hazmat: Oct 21, 2009 - 9:20 AM

You sure you don't have any vacuum leaks? It could be a really small one.

sure thats the easy/expensive way. but i mean you can check your voltage make sure that it has enough power. if you let go of the clutch when u put it in first, does it cut off?

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No clue. Wouldn't even know in the slightest where to begin to see if I do or not


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Cut off as in it not doing it anymore or? I haven't checked that yet. It just comes and goes. I've also noticed that I can curve it by turning on my lights. Soon as I turn the lights on my idle goes up a little, sits lower when I don't have lights on at all.

That definitely sounds like an alternator issue to me then, since it has to do with electrical load...

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You may be right. I've always noticed that when I turn on the lights my idle will sit higher ( right below 1k where it should sit regardless of lights on or off right? ) and at night when I have my lights on and when I got to brake I can see my lights dim a little when I do it. All my internal lights will dim a little too when I use power windows aswell. Guess I should find a new alternator huh? Really had no idea an alternator had anything to do with engine idle.

This post has been edited by Hazmat: Oct 21, 2009 - 7:52 PM

im pretty sure it is the alternator. try taking the alternator itself to the advanced auto and they will check it out for free. and try it with the lights and a/c on . if it idles really low and it strarts shaking and it feels like its gonna turn off, u might need a new alternator and battery. but just to be safe take the alternator off and go to the advanced.

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I'm no expert at all, but it sounds like it. I have the same issue...using the power windows dims my interior and headlights. But it's not a huge issue, I'll probably upgrade when/if the alternator craps out.

Ok so I went and got my battery and alternator tested today and turns out the alternator is fine but my battery was bad. So I had them replace my battery with a new BOSCH one. I'll be keeping my eye on the idle issue to see if maybe it was the battery causing the alternator to work harder to keep it charged maybe? I tried out my turning on the lights to up the rpm a tad bit and it still does that so I'm guessing its normal on that part. Next oil change I plan to get my mechanics to check my vac lines and or run any diagnostics to see whats up.

best way to go. yea may have been just the battery

Well this will be the 4th day now that it has run crappy. I'll be taking it in on a free day from work but I'm still curious if I may be missing something? I still feel like its a vac leak somewhere in the system but I don't hear any audible hissing or such. Would a very small vac leak still cause this type of issue regardless of showing its hissing side? Also on a offtopic note what is the normal idle for a 7AFE without Lights/AC On? (seeing as having the A/C and or Lights on bumps the idle up a tad) I want to say just below 1k like 900 or so but if anyone has the definite answer I do appreciate it.

My normal idle is right around 800.

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Yeah see on a warm engine and when I'm not idling rough, I sit at like 650 if that. I always thought that seemed low

650 is low. I have the same issue as you where my idle is sometimes a little rough, I notice it when it's warm out and I have the AC on and music blasting. But if anything, it dips DOWN to 650, never stays there. That's very low.

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*Sigh* I figured as much Hopefully they can find out or not if it is indeed a vac leak but who knows.

Yeah, I could be wrong here, but Im sure that a vac leak will raise your idle. Ask Dillon, he was there when I was cleaning my TB and forgot to hook my vac lines back up. Speaking of the TB, did you happen to check your IAC. That seems to be a big culprit in bad idle around here.

This post has been edited by Spider77: Oct 26, 2009 - 4:29 PM

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I thought it could cause rough idle aswell? I know it can cause high idle that wont come down but I know it can cause low/rough idle from what I've read.

IAC? No clue on where that even is. Time to search! lol

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Idle Air Control valve. You know, when I had a real bad idle problem (it was low and rough), I cleaned my TB, adjusted my throttle cable (it was a little loose), and tweeked my a/c bypass valve (that was for when I ran the A/C). I also did the "big 3". Those 14 year old wires were on their last leg. As far as your IAC, a simple check with a multimeter would let you know if its malfunctioning.

Hmm good to know. I'll see what goes down when I take it into the shop. If that dosen't solve my problem me and dillon were going to do a tuneup wireset/plugs/dizzy cap/ etc to see if maybe thats whats up but I'm hoping the mechs will find whats going on. All else fails we can mess around with it one of these days...

A good tune up never hurts. And by all means, bring it over when you want, so you can get int there and gets all "hands on" with it. And with the ST, you'll have alot of room to work with.