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'99 Rattling/Hesitation/Poor MPG

Old 07-31-2006, 11:52 AM
Thread Starter
Join Date: Jul 2006
Posts: 1
gibbylt1 is an unknown quantity at this point
Default '99 Rattling/Hesitation/Poor MPG

Hey All,

I did some searching and found very little that helped...

There is an intermittent rattling sound coming from the motor. It seems to be louder with the AC on, particularly 1800-2200 RPM. I would also describe the sound as gravelly. The noise comes and goes as I accelerate (rapid on/off sound) and as it is making the noise, I notice a signficant amount of hesitation; as soon as the noise stops, the car surges a tad. Mileage is at 13.5-14 mpg.

Just bought the Blazer a month ago with 76,000, now has 79,000. In the first month, the dealer (under warranty) has replaced the following:

(used) MAF
(used) AC Compressor
fuel filter
flushed cooling system (rust-colored fluid?)
idler/pitman arms
ball joints
power mirror switch
windshield washer
front diff seal
trans output seal
oil lines
...think that's it

Any suggestions? Should have shelved my patriotism in favor of a 4Runner...

Old 07-31-2006, 01:27 PM
Join Date: May 2006
Posts: 39
LT1KICKER is an unknown quantity at this point
Default RE: '99 Rattling/Hesitation/Poor MPG

I have a 2000 blazer with the same amount of mileage. I have a rattle that has been there since I bought it. I believe it to be either the exhaust or a heatshield under the truck. The sound is the same as yours, but I notice no change in performance. Dex-Cool looks rusty if it's used fluid. It is orange out of the bottle. Your truck uses Dex-Cool (any GM 96 and newer does.).
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