Random Stalling

04TrailblazerLT

Original poster
Member
Jun 12, 2015
10
Have had my TB around a year and in that time it has randomly stalled maybe 10 times. Have cleaned Throttle body. New plugs and fuel filter. Not sure where to go from here. It will randomly idle rough a few seconds then stall. Usually it happens in gear at a red light or something. Any ideas?
 

Mike w

Member
Jun 24, 2014
287
Mine just did that yesterday, it's done it a few times. I too would like to know what caused this.
 

littleblazer

Member
Jul 6, 2014
9,265
Mines been doing it for the last year. Only when it's hot out. The fuel pump died yesterday.
 

Tiggerr

Member
Jun 6, 2013
1,324
Perrysburg, OH
Mine's always done it. Only when it's hot out and with AC on. My wife's 04 Malibu used to do the same thing. Never have been able to decipher it on either vehicle. GM quirk is all I can figure. Irritating to say the least.

My fuel pump has been replaced and still does it so I know that's not it.
 

Playsinsnow

Member
Nov 17, 2012
9,727
O2 sensor? My stalled a few times. CEL was intermittent. Been 7 yrs later and no problems.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
To the OP, when you cleaned the throttle body, did you disconnect the battery for at least 30 minutes?
 
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steveO

Member
Apr 6, 2012
91
Quite a few years back mine used to do the same thing... it would stall only when hot randomly.
Just prior to stalling it would act as if it was not getting fuel. Sometimes it was hard to get it restarted.
I changed the filters and the problem remained, I was also considering the fuel pump but it was ruled out.

In the end the problem resolved itself when I changed a clogged catalytic converter and the associated pre / post cat sensors.
I always wondered if the sensors may have been the cause all along and it was just operating within range to keep the PCM happy.
It never set a code, but it got to the point that it lost so much power that I had to floor it to go up a hill that I could previously climb with ease.
Bottom line... when I replaced the cat and the sensors it ran like new and never did it again.
I did not try just changing the sensors as I had moved past that. IE loss of power/ gas mileage.
Depending on your age and mileage, it wouldn't hurt to change the sensors if they have not been changed.
For what its worth, my gut tells me I might have prevented clogging up the cat if I had changed the sensors early on..
 
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Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I think it was just an accidental double post on his part.

I'm also thinking O2 sensor and possibly a vacuum leak but there aren't any codes to work with. This will be difficult to track down.
 
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littleblazer

Member
Jul 6, 2014
9,265
The way a friend of mine told me he did it a long time ago was he kept it hooked up to the tech 2 and searched. His ended up being a tps that would occasionally die for a second. Since most people can't do that, its trial and error... well guess and check more so. Maybe a fuel pressure regulator? Mine was gradual. Like when you pull the relay to drop the fuel pressure for a filter change.
 

04TrailblazerLT

Original poster
Member
Jun 12, 2015
10
Thank you everyone for your advice. i was getting ready to upgrade my exhaust system and change O2 senors jus hit 150k miles. hopefully that helps. i will post if i happen to notice achange.
 

webdawg

Member
Jun 26, 2014
247
I was having issues similar to this. I followed all the steps (throttle body, spark plugs, ignition coils, fuel filter, fuel regulator, ignition switch) and it got better.

The car still ran rough.

A while ago I saw oil leaking out of my Camshaft Actuator/Camshaft Position Actuator Solenoid and I have been meaning to take a deeper look at it.

I was going to take it out last weekend, and before that months ago, to clean it and take a look at it...( http://forums.trailvoy.com/showthread.php?t=62398 ).

There was a ton of oil in the connector and I figured it was really bad. I replaced it and I cannot believe the difference.

At the same time I did replace the motor mounts (they suck on 4WD), but I can tell the difference it made in how the engine idles and performs.

I would check yours out.
 
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mross

Member
Mar 20, 2016
4
Dartmouth, NS
Thank you everyone for your advice. i was getting ready to upgrade my exhaust system and change O2 senors jus hit 150k miles. hopefully that helps. i will post if i happen to notice achange.
Did that ever work for you, I had my cat changed out because it wouldnt go up the hill because of the blockage ran perfect for 1000 km now is doing the same thing ,stalling off of highway and sometimes city driving. I'm going to change the first 02 sensor and see if that works also going to look at the camshaft position actuator solieniod
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I doubt you'll get an answer from that particular member. he hasn't looged on since last Aug.
 

smt 59

Member
Stalling out is usually the TPS going bad. Try cleaning the TB first, are there any other symtoms(shifting, rough up and down idle, engine light, poor of the start power)?
 

webdawg

Member
Jun 26, 2014
247
You are getting no codes or anything? What your talking about, without any diag, could be a million things.
 

mross

Member
Mar 20, 2016
4
Dartmouth, NS
Stalling out is usually the TPS going bad. Try cleaning the TB first, are there any other symtoms(shifting, rough up and down idle, engine light, poor of the start power)?
I have all of them will stall out when stopping at lights sometimes, rough up and down idle. I had no codes until today which was the p1345 and had a pending code of p0340. Before tonight it was giving nothing at all. When the issue first started I did clean the TB because it was horrible and that never fixed the issue nor made it worse does the same thing.
 

webdawg

Member
Jun 26, 2014
247
http://www.autocodes.com/p1345_chevrolet.html

Crankshaft Position-Camshaft Position Correlation

That is a bad one really. If your camshaft is not aligned with your crankshaft that is a big deal. How many miles on the vehicle?

I think your saving grace with that code would be the P0340 if it turns out to not be the Camshaft Position Actuator Solenoid. P0340 is Camshaft Position Sensor Circuit Malfunction. I do not know much about that one but I would look at wiring and sensors. It could have been that you were messing around with the camshaft position sensor and forgot to plug it back in before you turned the ignition on?

So did you check out your Camshaft Position Actuator Solenoid? If there is oil leaking out of the back of it, it needs replaced. If the screen is bad, it needs replaced. I replaced mine and the engine did so much better. I was having stalling issues also. I think this could be a/the cause. I just had this issue on a 2010 Equinox and that is the first recommended fix/part to try.

Did you change your crankshaft position sensor (don't unless it is bad) for any reason? Some people take them out and clean the gunk off of them. I changed mine for the heck of it (stupid) and did not realize that you need a relearn afterwards. So many misfires.
 

mross

Member
Mar 20, 2016
4
Dartmouth, NS
I did not change the sensor. The Camshaft solenoid it at first like most people there was oil in the connector and it was not only clogged but stuck in there good I suspect its original. After installation of the CPAS the check engine light went off but the stalling happened again tonight a day after I put it in seemed like it was running great the code is not popping at all when before I would clear it to see what condition it came back in usually under the stalling and today it never.

My truck seems to be running at 96 - 94 C, 201-205 F it does have horrible mileage I only have a Bluetooth scanner but from what I notice is when is sometimes it says open loop due to insufficient temp.

I'm going to change the fuel filter and test the fuel pressure but I suspect it is OK under idle when your not stopping it never stalls. The only time it usually stalls is approaching a stop or accelerating and than it bogs down but it some what seems like maybe too much gas is being dumped in and than its taking too much away because the fuel trims go all whack so it leads me to believe its not the fuel pressure but you never know.

If I have the push the pedal to the floor it it will pretty much never die but living in a city you do have to stop often so that always hard to do when your stopped.


I'm thinking possibly a faulty cam sensor, fuel pressure regulator, thermostat, or oil sending unit could cause symptoms like that. I am not the original owner but it seemed that most things were done that needed to be a trouble than they gave up.

Things I have replaced or done:
CPAS - Camshaft Position Actuator Solieniod - AKA VVT soliniod - It had oil in the connector and was stuck so it was time to be changed after 219,000 KM

Done an engine flush changed oil filters right before installing the CPAS

Got a new catalytic converter the old one was clogged which I suspect was caused by whatever underlying issue is going on.

I got a new o2 sensor which I think is just crappy its an NGK which apparently are the same maker of AC DELCO but it seems to be off so I'm going to return that and get a new one because the readings go real crazy the connector is perfect and all the wires going too and from is fine.

Had a new alternator put in because the other was shot


What I am going to do -

Visually inspect the crankshaft position sensor and I seen a handy video of a voltage test on line to actually verify if it is working correctly to this point I never even unplugged the sensor because I wanted to try the other part as it was really clogged anyways.

I'm going to somehow test the fuel pressure regulator and see if that helps and the fuel pressure

I'm going to visually inspect the thermostat but after 219,000 km or 136,000 MI I would suspect they would start to fail after so long.

Figure out a way to know if the TBS is actually not actuating or working...

and take back the o2 sensor and get another one and because the connector is fine.
 

Christopher

Member
Mar 13, 2016
8
Worcester
I had stall problems with my 04, one issue was the a.c. cluch. Of the system is not prober filled or cloves maybe at the orfice tube could cause the stall, remember that of the defrost is on that runs thew the a.c.. Also the variable timing silonoid next to PS pump. If you replace make sure the new part has screens on the side some such as doorman do not. They are cheaper but will give you lots of problems
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I wouldn't touch the crank sensor unless it's the last thing to check. If you disturb it at all, you may need a CASE relearn, which means a trip to the dealer.

If the temp is running low and goes into open loop, then I would suspect the thermostat. In open loop, it will dump extra fuel into the engine thinking it's cold, causing lower mileage and clogging the cat. With a bluetooth interface, you should be able to use Torque (Android) and check how the temperature is holding.

Someone else had reported that changing the fuel pressure regulator made a difference in mileage and drivability. Could be worth a shot.
 

mross

Member
Mar 20, 2016
4
Dartmouth, NS
I have the torque app but bought a crappy blue tooth reader going to order a better one this time. It was giving me temps between 94 and 96 which is 201-205 F so I'm going to see what the actual temp is supposed to be from reading it seems in the right range but it seems with the gas its burning it would be super hot. I do not want a case relearn so I will not touch that for now because I have seen multiple threads about messing with the cps and bad things happening until case relearn. I probably read everyone to do with stalling here and on trailvoy so I'm going to look for a regulator and see what happens.

I had stall problems with my 04, one issue was the a.c. cluch. Of the system is not prober filled or cloves maybe at the orfice tube could cause the stall, remember that of the defrost is on that runs thew the a.c.. Also the variable timing silonoid next to PS pump. If you replace make sure the new part has screens on the side some such as doorman do not. They are cheaper but will give you lots of problems

When I put my heat or push the ac button or put on defrost it makes no difference in the running of the vehicle, I have just been driving and pushed all the heater buttons and different variations and that didn't make a difference. The a/c doesnt seem to work which I don't use much living in a climate area.
 
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webdawg

Member
Jun 26, 2014
247
I wouldn't touch the crank sensor unless it's the last thing to check. If you disturb it at all, you may need a CASE relearn, which means a trip to the dealer.

I guess I will have to keep that in mind before I talk about it next time.
 

chogardjr

Member
Mar 29, 2016
3
Texas
This might be completely unrelated but I had stalls the same as everyone else. I cleaned the TB like everyone else and it helped a lot. BUT it always seemed like it was a power issue. I have done the tests of turning stuff on and off and didn't make a difference. So I had decided I wanted to throw LEDs throughout and see if that helps (needed this to help with Sub Amp power control without a CAP). At the same time I had the blower resistor (auto A/C) go out. So I LEDed it up and replaced the blower resistor (besides also removing the CAP from Amp) and it has yet to do it anymore after 2 years.

Like I said it could be unrelated. But I did feel it was a power issue and the blower resistor wires were exposed and grounding out. It did not show signs of being involved with a power drain when doing my tests, just keep that in mind. I should hooked the multi to it when it was doing that to see but I was more interested in not being without a A/C blower in the middle of summer :wink:
 
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