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2002 chevy trailblazer_ls
11 Posts
Discussion Starter · #1 ·
so today im driving home from houston texas i45 ya know i change lanes see a jerkwad coming get on it and notice a loss of power well then i hit the traffic and hear a thump under the hood reassuring myself it wasnt me i slipped it into neautral however you spell iy lol and revved it up it was me all right so i pulled over to look under the hood sat in a parking lot looked under the hood contined to hear the noise until the motor died:hissy: best described by my gf as putting the tab of a soda in the can and shaking it so whats you guys thoughts? it has 133000 miles but its pretty well maintanined its the 4.2 whats going on under my hood im stranded in houston tryng to get home!!!!!

2004 chevy trailblazer_lt
1,298 Posts
You see any SES light activity?

Could you tell where that rattle was coming from? If it was down in the exhaust,
your cat might have come apart inside, and might be causing backpressure
that kills the engine.

Was the "thump" happening on a regular interval, or was it erratic? Regular
might point to a firing issue or solenoid/valve activity. Erratic could be something
fallen loose.

If it's coming from the head, could be a part of the valve train has come apart.
Friend of mine lost a valve keeper on a rebuild head for his 350SB. Sounded
a bit like a rattle, before the valve got punched through the cylinder... :(

Check vacuum lines. Vacuum failure can cause all sorts of problems.

Could even be a failed actuator/solenoid, but there are a lot of possibilities that
it *could* be that would kill the engine, and we'd still be guessing.

See if you can get any codes out of it, or narrow down the location of the sound.
You might be able to exclude or verify the cat issue by removing the upstream
O2 sensor and if the truck starts.

Good Luck!

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