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99 Denali power loss..

shorgasm

By shorgasm
in Ask A GM Technician

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shorgasm Enthusiast

shorgasm

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5.7 Vortec.110k on her...been running alright BUT the power has been "off".It started at about 5500rpm then down to 4500rpm's and finally now she won't rev past 3000rpm's under load....I know..It's either fuel spark or air..Filter is good and mechanical she is perfect...The fuel is were I believe the issue is at.The pump has been doing an odd thing over the last month or so.Cold and for the first say 20-30 minutes the pump is normal tone/whine..then all of a suddne it doubles in volume and sounds like it is speeding up.The power is off requardless of the time or noise.Hot or cold she won't rev out in gear..1st 2nd 3rd whatever same result.She runs strong right up to around 3K and and just stumbles...No hard jerking or anything violent but it's done and the trip to 5500rpm's.

 

I have only had this truck for about 4 mths..I have no idea of the Fule filter condition but I am guessing the pump is on its way out?....I got a quote of $120 for labor if I provide the assembly?

 

No lights or codes visible ever...gas mileage is kinda hit or miss...I drive the same and the mileage varies greatly.Odd?

shorgasm Enthusiast

shorgasm

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Did a search and found a longer post in 2003 that ended up being a leaky regulator....Are these hard to get to?

 

I'm pretty mechanical able...to a point of course.

 

1.FPR?

2..Plugs?..not likely I would think

3...Fuel pump...I sure hope not..

4....catalytic's are about shot?...could be this too..

5.....Muffler has been doing a Popping thing for a long time..heat cycle/expansion pop that happens only after the truck first starts up and gets warm.The Muffler "pops" once.Kinda like a baking sheet in an oven.When you heat or cool it too fast.

shorgasm Enthusiast

shorgasm

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Sumbitch....It was the fuel filter...Go figure...$5 and 10 minutes all done..Cranked her up and she sounded different..mashed the gas and she hit the rev-limiter like a firecracker....

 

 

So just for s**ts&giggles..I picked the old filter(acdelco) and tried blowing threw it as hard as i could...No way no how not happening..I have never had a fuel filter at least not let some air through.The new filter you literally feel the same pressure you putting into it...and yes I drained the new one first

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