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2003 chevy trailblazer_lt
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Discussion Starter · #1 ·
Hello all
I recently rented a small 5x8 UHaul trailer and traveled from Maine to South Carolina. I packed the trailer with a queen bed, a small coffee table, 5 totes full of clothes, pots and pans, curtains etc....there was not too much weight total and most of the heavy stuff was centered over the axle. Anyways i noticed that it was sluggish while driving, which I expected. But as I got further south and into warmer air (80's) it seemed to get worse, and then it shifted out of overdrive and would not go back in. No CEL or anything, fuel milage was about 14. Now whenever its warm out and I'm driving to work or whatever, it seems to be sluggish, even worse when the A/C is on.
Now last summer while I was stationed down here I had the same problems. I thought it was dirty throttle body so I cleaned that via the How-To, replaced the spark plugs with OEM AC DELCO and ran a bottle of Techron through it. Also let the car sit 8 hours while at work with the battery unplugged. Car just turned 96,000 miles, never had a trans service but fluid is up and still pink/no burnt smell and run Mobil 1 5-30w. Could it be a plugged catalytic converter?
 

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2004 gmc
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IIRC, overdrive gets locked out if the tranny overheats. I would guess clogged cat, but not sure other than observing symptoms how to diagnose that. Also, you're overdue for a transfer case service as well as the transmission. Check the Owner's Manual.
 

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2003 chevy trailblazer_lt
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Discussion Starter · #4 ·
IIRC, overdrive gets locked out if the tranny overheats. I would guess clogged cat, but not sure other than observing symptoms how to diagnose that. Also, you're overdue for a transfer case service as well as the transmission. Check the Owner's Manual.
I realize this, I had a small pinion seal leak and took it in for replacement. While it was in there I asked about the tranny filter change or flush, not really sure which one to do, or both. THey quoted me $535 for a flush, transfercase service as well as front/rear diffs. Thought that was kinda pricey so I'm looking elsewhere.
I found the Magnaflow direct replacement cat online, debating on buying it and swapping it out. Should I replace the O2 sensors while its out as well? Or am I just wasting my money?

I would also look into the front O2 sensor. Cheap enough to replace.
IIRC, if the O2 sensor was bad, wouldn't it throw a CEL?
A guy on base has a turned up Duramax, he uses EFILive, was talking to him and he said he could hook up his laptop to my car and monitor it while driving and see what we can find.

Would a bad AIT sensor make the car sluggish? I had a 99 Eclipse GSX turbo and it had a bad AIT sensor, reading that the intake charge was hotter than it was, thus reducing timing to prevent detonation.
 

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Discussion Starter · #5 ·
Another thing.....when you take off and floor it, it's sluggish until 4500-5000 rpms then it takes right off till it shifts to second, then its sluggish again. Havent maxed second out, don't have the room on the roads around here. Seems like a timing issue....like the ecu is retarding timing up to that rpm.
 

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An O2 sensor can operate in a lazy mode without throwing a code, and
it will cause sluggishness. DIY on the tranny flush and rear diffs will cost
around $100-$200 depending on what fluids are used. So you can use that to compare.
 

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Discussion Starter · #7 ·
Thanks on the tip. I checked AMSOIL website and with the filter, tranny fluid, front and rear 75-90w oil it came to $198. Can't get the transfer case fluid as its a GM only oil, really don't want to see the price on that stuff.
We'll see what shows up on EFILive, see if the front and rear O2 sensors are fluctuating like they should be.
 

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I'm not sure if my problem falls in the same lines or not but here goes...

I normally drive by RPM and try to keep it below 2200. Well here recently I have been in a hurry a few times and I have noticed that if I hit 2600-2800 RPM it feels like a afterburner kicking in and the truck just takes off. Any ideas if this is normal or if I need to change something? I have done all my scheduled maintenance. Also, it is not changing gears when this occurs.
 

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2004 gmc
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Autotrac II fluid is only about $8 a quart at dealers and you need two quarts. Could be worse.

On the afterburner issue, it might be you're being strangled by torque management. A tune can release all the HP you've paid for out of the engine. PCMforless is having a memorial day sale.
 

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Discussion Starter · #11 ·
Autotrac II fluid is only about $8 a quart at dealers and you need two quarts. Could be worse.

On the afterburner issue, it might be you're being strangled by torque management. A tune can release all the HP you've paid for out of the engine. PCMforless is having a memorial day sale.
Roadie....when you said earlier i needed a transfer case service, is it just drain/refill, or do they actually do something inside the transfer? If its just drain/refill, then I can do all this stuff myself right here on base on the weekend. They have the lift and all the tools to do it as well as the fluid catch pans.
 

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Transfer case is just a drain and fill. You will need a hex head socket to remove the plug.

On my TB. I had noticed it being sluggish on takeoff, then picked up. I had no code but I changed my front O2 sensor. It was better immediately.
 

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Get your buddy to scan both the front and rear O2 sensors, I just replaced both on my 02 I6 with 105,8xx mi last friday before I headed to Spokane for saturday. Mileage didnt really change, got 20mpg at 72mph there and back with probably 10-20mi of city driving too. Regular gas, with my premium tune I get a little better.

xfer case is easy to go, get a hex bolt (cant tell you what size it is, sorry) and 2qts of AutoTrak II fluid. Drain and refill. Same with the diffs, think you need like 3.5qts of 75W-90 diff lube (preferably synthetic, like Mobil 1 or Amsoil).

For the sluggishness, its just the way GM programmed these from the factory. Get your buddy with EFILive to tune your TB, pay for the license (99 bucks) and drop me a PM, Ill point you in the right direction if you want.
 
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