04 trailblazer stalling

Rhino

Original poster
Member
Oct 8, 2012
4
Hey guys, new to the forum and I like it. I have been chasing a ghost in my 04 trailblazer. I recently changes the cracked exauhst manifold but didn't change the o2 sensor until about a week later. I went out of town for my daughters doctors appointment and noticed it stalling at red lights and was surging when I took off. Once you were going it would run fine. I read some forums about cleaning the throttle body and so I did that and yes I unhooked the battery. Now the engine idles better but when you first start driving it kinda falls on it's face stalling put picks back up and goes. It only does this with the ac on and before the temperature is at operating range. No codes. Also since i unhooked the battery I am also chasing those stupid ac door motors. I'm about to get that worked out. If you guys could help on the stallin I would appreciate your time
 

McGMT

Member
Jun 17, 2012
621
Rhino said:
Hey guys, new to the forum and I like it. I have been chasing a ghost in my 04 trailblazer. I recently changes the cracked exauhst manifold but didn't change the o2 sensor until about a week later. I went out of town for my daughters doctors appointment and noticed it stalling at red lights and was surging when I took off. Once you were going it would run fine. I read some forums about cleaning the throttle body and so I did that and yes I unhooked the battery. Now the engine idles better but when you first start driving it kinda falls on it's face stalling put picks back up and goes. It only does this with the ac on and before the temperature is at operating range. No codes. Also since i unhooked the battery I am also chasing those stupid ac door motors. I'm about to get that worked out. If you guys could help on the stallin I would appreciate your time

How many miles you have on it? What is your service history, plugs and such? Give us the whole 9 yards.
 

Rhino

Original poster
Member
Oct 8, 2012
4
McGMT said:
How many miles you have on it? What is your service history, plugs and such? Give us the whole 9 yards.
It has 140 thousand miles and plugs were changed at 85,000. Not sure but I believe I used original equip on there. Just changed fuel filter and checked fuel pressure. I had someone get in and power brake as I checked pressure and it was holding at 52 psi. It held that pressure even when it started to lug down. I also changed the charcoal canister. Other than that it's about it. It's been a good vehicle.
 

McGMT

Member
Jun 17, 2012
621
Rhino said:
It has 140 thousand miles and plugs were changed at 85,000. Not sure but I believe I used original equip on there. Just changed fuel filter and checked fuel pressure. I had someone get in and power brake as I checked pressure and it was holding at 52 psi. It held that pressure even when it started to lug down. I also changed the charcoal canister. Other than that it's about it. It's been a good vehicle.

52 doesn't seem right to me, I know that this is different but on the old 4.3 spider injected engines 52 was absolute minimum pressure.. Paging Dr. Roadie, what does your GM service manual say for fuel pressure?
 

Rhino

Original poster
Member
Oct 8, 2012
4
McGMT said:
52 doesn't seem right to me, I know that this is different but on the old 4.3 spider injected engines 52 was absolute minimum pressure.. Paging Dr. Roadie, what does your GM service manual say for fuel pressure?

I was thinking 50 to 55 but I certainly will double check
Thanks for your input so far. I have bee racking my brain and reading thread after thread.
 

gmcman

Member
Dec 12, 2011
4,656
Welcome to the club.:thumbsup:
You stated you were not sure about the plugs, because of this, I suggest you pull one of the plugs and tell us what they are, and if AC then note the number on the plug. Reason I say this is these engines like the AC plugs ONLY, no exception...preferably the newer iridium plugs.

Check the big vacuum hose under the front of the large plastic intake baffle and ensure it's connected, you could have overlooked this when reinstalling.
 

Rhino

Original poster
Member
Oct 8, 2012
4
gmcman said:
Welcome to the club.:thumbsup:
You stated you were not sure about the plugs, because of this, I suggest you pull one of the plugs and tell us what they are, and if AC then note the number on the plug. Reason I say this is these engines like the AC plugs ONLY, no exception...preferably the newer iridium plugs.

Check the big vacuum hose under the front of the large plastic intake baffle and ensure it's connected, you could have overlooked this when reinstalling.

I will check both items you mentioned tonight when I get a chance to look at it and respond with results. It sounds too simple to so hard to figure out the problem.
 

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