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Discussion Starter · #1 ·
I am looking at a 95 ss to buy, when I first started it, it stalled and the guy said oh ya you have to hold the gas for a bit. It seems the truck thinks it is warm and wants to idle at warm temps (maybe). After a few seconds it would idle on its own. Then the truck ran great, no problems running, stopping, accelerating. I am still going to buy the truck as I am a sucker for punishment lol. I also have wanted an ss since highschool, and have already owned most other forms of s10.

I am picking the truck up next weekend, Im just looking for some possible causes for this issue for me to educate myself on before getting the truck.
Thanks in advance.
 

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could be the Idle air control, the engine coolant temp sensor, or EGR valve issue thats what i would look at first and i would clean the IAC and the EGR and there ports first and see if that fixes the problem and then go from there
 

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and if none the above common causes are the cause then check FP pressure, but bet it is something very minor, IE lack of regular maintainence and parts removal and cleaning in which most ppl wont do and then they wonder why they start running bad
 

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Discussion Starter · #4 ·
Thanks guys, I assumed it would be something simple which is why I still commited to buy it.

The truck just passed the etest in october so I doubt the problem is in the egr but it is easy enough to check and clean. I figure the problem is temp related but I am not overly familiar with these kind of issue as every chevy Ive owned in the past has ran great and was maintained.

My first thought when I went to start it was fuel pressure so I cycled the key and waited in ON pos. before firing, but no difference. Def. a likely cause though.

Well 5 days till I pick it up. I am actually anxious to get it... weird.
 

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Discussion Starter · #5 ·
Alright got the truck home now, it drove nice all the way home about an hour and half drive.

I seems when the truck is warm and you start it the rpms hit about 1300 from the initial fire then drop down to like 400 rpms then idle at about 600rpms.

So when the truck is cold it does the same thing only it stalls due to being cold. The rpms are about 1000 when idling on its own when cold which seems about right.

I need to figure out what causes this rpm drop right after it fires, any help appreciated. I am going to clean the egr and maf today along with spark plugs. Gonna get familiar with my new baby.
 

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Discussion Starter · #6 ·
I just noticed that the temp guage sits slightly over 40 when the truck is completely cold, wondering if this could be related to my stalling issues.

Also I checked and cleaned egr and iac did not see any noticable problem with either. The seat on the iac had a bit of carbon making the seat uneven but that is now clean but no difference with truck.
 

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Discussion Starter · #7 ·
Anyone have more suggestions, I ordered a new muffler today and decided to get a new temp sensor, they are cheap and easy to change so why not. I need to get to the bottom of the problem so my gf can drive the truck too.

I starting to think there is a possible vacuum issue as when it is started while warm it fires then the idle fluctuates from about 1100 down to about 400 it does this about 3 times up and down then it holds at about 7 or 800rpm. I also noticed sometimes at stop the idle will fluctuate slighty.

Haynes manual says could be intake manifold gasket, I dont know, please help.
 

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it sounds like it could be a vacuum issue it also could still be an issue with the egr valve how well did the plunger move up and down while you were cleaning it it it did not move very good it could be the egr letting too much air back in to the intake
 

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oh also i forgot to add that you could hook up a vacuum gauge and see where your vacuum is running at this test could help you determine if you do have a vacuum leak or possibly a intake gasket leak. you can do the old trick of spraying carb cleaner around the gaskets and see if the rpms change and you can do this on your vacuum lines and see what that does
 

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Discussion Starter · #10 ·
the egr valve was not sticky in the slightest, moved very well before i cleaned it.

I starting to think maybe there is a vacuum issue now since when started when warm the idle will drop and rise a few times before holding steady.

sometimes while stopped at a light the idle will fluctuate a little.

I picked up a new muffler today along with coolant temp sensor so we can see what that does, not expecting anything now.
 

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Discussion Starter · #12 ·
How many coolant temp sensors on this thing the one I bought is different than the one on the driver side cylinder head, I was told at the part store that the one they gave me is for the pcm, and there is another for the temp guage, I am not sure where the other is located and in the haynes manual it says there is only one on cylinder head. I dont know.

Now the truck when i first pull away and I give it a quick shot of gas and let off it stalls, im leaning towards vacuum issues now, i have to get a guage.

I got a check engine light now so maybe this will help me. Who knows.

Also it looks like most vacuum lines are new, i will replace the rest soon. I did find that the little boot on the pcv was very sloppy so i used a small peice of hose to connect the pcv to the tube that goes to the intake.
 

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there are 2 coolant temp sensors the one in the drivers side head is for the temp guage on the dash the other coolant temp sensor is on the intake and that is the one for the computer
 

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Discussion Starter · #14 ·
ok I changed the one on the drivers side, i didnt see the other one so i brought the sensor back, I was hoping the one on the driver side was for the computer, since that is the one i wanted to change.

I dont think that is the problem, the idle will fluctuate and almost stall sometimes when approaching stop and while stopped. The odd time it will stall. I think maybe a bad iac on its way out. Does anyone know a good way to clean this, I had a can of quick start kicking around a used this to break down the carbon on the plunger. It didnt seem that there was much more u could clean on it.
 

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Discussion Starter · #15 ·
Oh ya, I also checked fp and it is right at the top end of specs, ON, and running. So ive ruled that out, it must be a sensor issue of some sort.
 

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sweet glad to hear that all is well again
 
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