Mechanics

S10 BLAZER IDLES ROUGH AND STALLS OUT

1995 Chevrolet Trailblazer

My problem started after driving 511 miles home from kansas. I was comming up to my street to turn when the truck randomly decided to stall. Thinking I was out of gas I checked the gauge fine I had 1/4 of a tank. Took a few minutes to get it to restart. Then when I got home I changed the plugs and wires. That didnt fix the problem So the next morning I went and had codes pulled on it no idiot light come on either but for some reason there was code for a bad air check temp sen so I replaced it didnt fix it. Next code come up that the air control motor was bad replaced it and still didnt fix it. Next code said I hade a bad tps throttle position sen. Replaced it still nothing. Any sugestion on what to check next? Joe
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Buellxb9rfb
August 15, 2006.




So the problem is it keeps stalling? When this happens does it put out a little black smoke? I have heard of the hard plastic fuel lines cracking and running fuel in the intake. Not sure which engine model you have, but I would have the fuel pressure system tested and try and find out if it is stalling for a too rich, or too lean mixture. A faulty injector could be a cause. You just need to have it checked out and see whats going on.
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Tiny
Mikeybdman
Aug 15, 2006.
So the problem is it keeps stalling? When this happens does it put out a little black smoke? I have heard of the hard plastic fuel lines cracking and running fuel in the intake. Not sure which engine model you have, but I would have the fuel pressure system tested and try and find out if it is stalling for a too rich, or too lean mixture. A faulty injector could be a cause. You just need to have it checked out and see whats going on.[/Quote: 7f657ce19a]

YEs the problem is that it is still running rough and stalling out. There is a very rich smell comming from the exhuast and no smoke that I have seen. The motor is a 4.3 vortec 6. The truck runs fine once you get it going but as soon as you slow down or stop it trys to stall out most the time it does stall

Tiny
Buellxb9rfb
Aug 15, 2006.
So the problem is it keeps stalling? When this happens does it put out a little black smoke? I have heard of the hard plastic fuel lines cracking and running fuel in the intake. Not sure which engine model you have, but I would have the fuel pressure system tested and try and find out if it is stalling for a too rich, or too lean mixture. A faulty injector could be a cause. You just need to have it checked out and see whats going on.[/Quote: fc3bca923a]

YEs the problem is that it is still running rough and stalling out. There is a very rich smell comming from the exhuast and no smoke that I have seen. The motor is a 4.3 vortec 6. The truck runs fine once you get it going but as soon as you slow down or stop it trys to stall out most the time it does stall[/quote: fc3bca923a]

With a smell of fuel, I would suspect a possible leak in the intake. Its not that hard to remove the upper intake, and look at the MFI injector system. I would pay particular attention to the fuel tubes and see if they are old, brittle and cracking.
This model also has a history of having sticky CPI poppet valves. You can have those cleaned, but it takes special equipment to run the cleaner thru the system.

Tiny
Mikeybdman
Aug 15, 2006.
So the problem is it keeps stalling? When this happens does it put out a little black smoke? I have heard of the hard plastic fuel lines cracking and running fuel in the intake. Not sure which engine model you have, but I would have the fuel pressure system tested and try and find out if it is stalling for a too rich, or too lean mixture. A faulty injector could be a cause. You just need to have it checked out and see whats going on.[/Quote: b7aab90bdb]

YEs the problem is that it is still running rough and stalling out. There is a very rich smell comming from the exhuast and no smoke that I have seen. The motor is a 4.3 vortec 6. The truck runs fine once you get it going but as soon as you slow down or stop it trys to stall out most the time it does stall[/quote: b7aab90bdb]

With a smell of fuel, I would suspect a possible leak in the intake. Its not that hard to remove the upper intake, and look at the MFI injector system. I would pay particular attention to the fuel tubes and see if they are old, brittle and cracking.
This model also has a history of having sticky CPI poppet valves. You can have those cleaned, but it takes special equipment to run the cleaner thru the system.[/Quote: b7aab90bdb]

had all that replace not even 6 months ago. Is it possible that it could be cap and roter?

Tiny
Buellxb9rfb
Aug 15, 2006.
I can see the cap and rotor causing the truck to run a little ruff, but I would think it would be ruff at most all speeds and conditions. Shouldnt be too much trouble to take the cap off and look to see how the contacts look.

Tiny
Mikeybdman
Aug 15, 2006.
Mikey I found out last night thaat the reason it was stalling out was cause the parts house sold me the wrond tps. Changed that out and it fixed the stalling problem. But I still have a rough idle, now I have been told by two differnet mechanics that I have the wrong plugs in my blazer and that I should have acdelco plugs in it. I put champion copper plus in it. Could this be the proble as to my rough idle. I have also had other mechanics tell me it make a difference what brand I put in it that it should run fine. Any info on this would be helpful thanks in advanced. JOE

Tiny
Buellxb9rfb
Aug 16, 2006.
Mikey I found out last night thaat the reason it was stalling out was cause the parts house sold me the wrond tps. Changed that out and it fixed the stalling problem. But I still have a rough idle, now I have been told by two differnet mechanics that I have the wrong plugs in my blazer and that I should have acdelco plugs in it. I put champion copper plus in it. Could this be the proble as to my rough idle. I have also had other mechanics tell me it make a difference what brand I put in it that it should run fine. Any info on this would be helpful thanks in advanced. JOE[/quote: 42e608ab1a]

I have heard in some cases that different plugs can effect fuel burn pattern, and even how much of the mixture is burned. Is this what is making your idle rough? Only one way to find out.
I always use OEM plugs. Basically that means whatever was the Original Equipment placed in the engine by the manufactor. So whatever plugs the book calls for as the OEM plugs, is what I would use.
I will tell you that there are a ton of things that can make an engine run a little rough. One injector giving a bit too much or little of fuel. A very small vacuum leak. One plug wire having too high of resistance. Just a whole list of things. I have even heard of a weak battery causing it.
I know my S10 4.3L feels more rough than my 3.8L Grand Prix motor, but it still runs good, and gets good gas milage. I dont think that engine would ever be as smooth, based on the type of exhaust, fuel delivery system. Ect.
But having a small idle flux of around 50 rpm or so is probably not all that bad as long as the engine isnt trying to stall, or starving for fuel or loading up too much.

Tiny
Mikeybdman
Aug 16, 2006.
Come to find out after taking it to the shop I found it was just a clogged egr valve. Had it cleaned and put back on and ran like a champ the guy said its a normal problem with that year 1995 mfi injection systme

Tiny
Buellxb9rfb
Oct 21, 2006.

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