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Discussion Starter · #1 ·
Three issues I need help with.

First history of the Trailblazer. 05 LT I6. About 7,000 miles ago or less the car was in for constant lag when trying to accelerate like the transmission wasn't shifting. It turns out one of the cylinders did not have compression and they replaced the cylinder head ($4k+) they also changed the thermostat and the oil at the time. The mechanic mentioned there was some lifter tick but I have not noticed anything really bad. They also had to fix something with the exhaust manifold after I got it back - I heard a ticking. Everything seemed ok except:

Ever since I got the car back I have noticed there seems to be a low hum with very little vibration on when at idle or stopped while in drive. It has been driving me nuts. It's not rough but just seems to be a lot more low drone when just sitting at a light.

Also when I tap the gas from a stand still it stutters. The car starts to move but if I take my foot off the gas too quick (let's say in a parking lot) it stutters and I see the revs drop as I let off the gas then they surge. The car lurches a little.

Last problem. This one I think is the fan clutch. It seems to be only at startup there is a ticking about 1 or 2 a second. I looked it up and it seems to be that.

So I figured why not try some new oil and filter. Put Valvoline Synthetic and Purolator Pure One on the car today. Engine seems smoother but the low drone is still there along with all the other issues. I figured it wouldn't fix it but it was time for an oil change.

Can anyone tell me what might be up with these issues? The car is on an extended warranty but I want to make sure these are issues that can be fixed before I go and plunk down $100 deductible. Thanks for the help!
 

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Droning noise might be the idler pulley. Take the serpentine belt off for a few minutes and see if it stops. Cheaper to change yourself than your deductible.

Ticking fan clutch might be early signs of deterioration, but many members report that with no long-term problems.

Stutter is probably a dirty throttle body. How many total miles on it? Is your idle stable at 600 RPM, even when the AC compressor cycles on and off?

http://forums.trailvoy.com/articles.php?do=viewarticle&artid=91
 

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Discussion Starter · #3 ·
60k miles on it. I think the idle is stable. I will watch it with the A/C on tomorrow. I am in Arizona so it's great that I have my A/C on all the time.

Never done belt work myself but I figure I can try it. So I just take the serpentine off - can I drive with it off? I would figure no. I should mention that the noise I hear is in the cabin not outside when I am at a stop with the break on or with the car in park. I don't hear anything odd when I listen to the engine except that ticking at startup.
 

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You reported the noise was worse in the cabin. The idler pulley is not in the cabin, so it could be a mouse in the HVAC blower motor or a hundred other things. An Internet forum really can't help you much unless you can describe more precisely where your noise is. If you can't, then you need a mechanic with good ears. Sorry.

You have a warranty, so you don't have to diagnose it yourself. Go make use of it.

You don't need a picture to know where the idler pulley is, if you're qualified to be changing it. It's the one that doesn't pivot on an arm. That's the tensioner pulley. But if you say the engine doesn't make noise, then that can't be it.
 

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Thanks - I guess... no need to be so harsh. I'm sure a mechanic could figure it out but was looking for information. What if they tell me it's nothing but it still bothers me? Can I be a cheap student? Can't I ask for help? If I could fix it for less than my $100 deductible than why wouldn't I? There is no way to better learn than to fix problems. I'm sorry I asked for help. I had read that the pulley was easy to change even for someone who is not qualified it seems.

To describe it more and answer your original questions. The idle seems stable. It seems to be a bit higher than 600rpm maybe 750 but I don't have any diagnostic computers etc. other than looking at the tach when I'm idling.

The sound is in the cabin, I can't hear it outside and seems like more of a vibration now that I listened to it more. It just bugs me because my car used to be very smooth but maybe I'm just being picky. If there is nothing else it could be I could just take it to the shop later. I just hope that when I don't have a warranty and ask a question I won't be belittled next time.

Thanks for trying to help everybody.
 

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2003 chevy trailblazer_ls
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Please fill out the UserCP at the top of the page.
The quote below describes you as being somewhat impatient. Not everybody on this site is on every day.
Can someone help with diagnosing if it is the idler pulley? Pictures or a description on what to do would be nice. I don't want to destroy my engine- thanks!
Roadie is not being harsh. He is one of the best here. To diagnose your problems takes more than you just saying "I have a drone in the cabin" I have seen that come from a business card drop to the blower fan through the defroster vents!

"Thanks - I guess... no need to be so harsh. I'm sure a mechanic could figure it out but was looking for information. What if they tell me it's nothing but it still bothers me? Can I be a cheap student? Can't I ask for help? If I could fix it for less than my $100 deductible than why wouldn't I? There is no way to better learn than to fix problems. I'm sorry I asked for help. I had read that the pulley was easy to change even for someone who is not qualified it seems.

To describe it more and answer your original questions. The idle seems stable. It seems to be a bit higher than 600rpm maybe 750 but I don't have any diagnostic computers etc. other than looking at the tach when I'm idling.

The sound is in the cabin, I can't hear it outside and seems like more of a vibration now that I listened to it more. It just bugs me because my car used to be very smooth but maybe I'm just being picky. If there is nothing else it could be I could just take it to the shop later. I just hope that when I don't have a warranty and ask a question I won't be belittled next time.

Thanks for trying to help everybody. "
Nobody is belittling you but you are giving information one piece at a time. Also your drone might be an exhaust leak anywhere along the exhaust system.
 

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You just came along at the end of a long day of volunteering here interspersed with cleaning my garage. And the parade of noobs was pretty intense. We had owners who refused to read their manuals because they were confusing, and therefore didn't know we had two fuse boxes. :confused: We have somebody with bald front tires complaining about their handling not being as rocket-like in corners as before. :duh: We have somebody who thinks a recent lift kit install destroyed their ball joints, but they coincidentally have 100K miles and the ball joints don't owe him a thing. :no: And it's an odd thought that an idler pulley problem can destroy your engine, but you are right to be cautious. I have to admit myself to a bit of caution. And a gigantic dose of cheapness. :yes:

The idler pulley mounts with a single bolt, a quick search here would show that people have bought them in the aftermarket stores for $20 or so, female owners have changed them with very little experience, and for $20, if you're suspicious of yours there's no downside to changing it out. Except the $20. Good luck, and don't write off the site because one member (me) had a tough day and snapped at you. :cry:
 

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Discussion Starter · #9 ·
Explanation: I didn't mean to sound impatient... I had waited several days and had read the threads about changing the pulley - hence why felt belittled that someone told me I had no reason to ask such a question. I wasn't going to do anything until I was sure that it might be a pulley issue.

I feel better that roadie explained his day. I'm sorry you had a bad day. I totally understand where you are coming from and I grateful you all can help me. There are idiots out there and it seems you might have thought I was one... understandably so after the day you had Roadie.

I'll have to get under the car and see if there is an issue with the exhaust. Maybe something is loose from when they pulled my engine to replace the head.

I'll fill out the CP for all those who are wondering.
 

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2006 chevy trailblazer_ls
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I have noticed a bad vibration when sitting idle. I plan to take it to the stealership for $95.32 to get diagnosis.

I have extended warranty and 38K miles. It seems there are many threads about vibrations.
 
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