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Chevy truck power problem


v00d00child

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I just bought a 94 chevy 2500 4x4 truck with a 350/manual with 180K on her. I'll be redoing my basement soon and need a heavy duty winter vehicle anyway, since I live on an unmaintained mountain road.

You could eat off the engine, and the owners seemed to have fixed things as they occurred (ie, they didn't run it into the ground). The engine starts, idles, and runs fine, and doesn't smoke/drink oil, but going uphill this thing feels like it couldn't pull the petals off a daisy. It's a 3 sp with OD + a granny gear, and going uphill, I can barely maintain speed in third. The plugs/wires/cap are all new, the air filter is pristine, and I'm currently running a bottle of SeaFoam thru the fuel system.

Keep in mind, I live at 8500' ASL, but even down in the city, this thing couldn't pass much. The odd thing is that it idles smoothly, doesn't stumble, or have any other problems that seem to narrow causes down for me. My thoughts:

Restrictive catalytic converter (not clogged, but restricted)

Bad EGR valve

Bad vapor canister

One of the last things the owner said was a comment about how it didn't feel like it had the power to pass that it usually did.

Any ideas on what might be causing this, and what quick checks I could do to test it???

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Check the fuel filter for restriction, and the exhaust, first.

Fuel filter is cheap, so slap a new one on, but try blowing through the old one in the direction the fuel flows. You should be able to blow through it easily once the fuel is out. If you have to strain at all, it's plugged.

Take the truck for a test drive, then remove the oxygen sensor (leaving it plugged in, but dangling) from the exhaust system. If power improves, you have a restricted exhaust, which may also be from the muffler. GM truck mufflers have a habit of breaking the baffles inside the muffler, and restricting the system.

Other than that, check the basics like timing, excessive cam chain slop, etc. I doubt it's an EGR or EVAP system problem.

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those trucks do often have those symtoms when the fuel sending unit on top of the tank corrodes, and/or the fuel filter gets clogged..

Other than that and the Auto/OD tranny that craps out like clockwork at 100K miles or so (which you obviously won't have to worry about), those trucks are pretty damn solid, in my experience...

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I'm back in WA now, had to leave the truck back in CO (if anyone would like to steal it, lemme know, and I'll put full coverage on it. Just don't plan on a "quick getaway").

Good info guys--I appreciate all the hints. Hopefully, I'll be back in CO for good inside of a month.

My hopes when buying the truck were that the previous owners had replaced pretty much everything that typically goes wrong, and that I'd be getting the "6 million dollar truck" for a good price. Now I'm just hoping that all the replaced parts aren't at the end of their lifespan.

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My guess..

Dirty Cat

or

Weak fuel pump.

Both will cause the symptoms you speak of, and I have delt with both.

On a side note.... my boss ran three or four cans of Lucas Fuel treatment through his motor... consecutively...

plugged the Cat, had to replace, runs great now.

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Eric-

Thanks. And DAMMIT!!!

I spoke with Mile-Hi muffler before I left CO, and they said they had a similar truck with similar problems in earlier, and it turned out to be fuel related. Starting to think I should just bite the bullet, replace the cat/exhaust, and pull the tank, just cuz they're all suspect, and probably need attention anyway.

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IF when you rev it up the exhaust sounds like it's Wooooooshing instead of rumbleing. I'ld go after the Cat.

It's a V8... so it should sound like one. It shouldn't sound like..... it's pushing air thruogh a straw.

Listen to other Chevy trucks as they drive by then yours... you'll know what I mean if it's bad.

As you accellerate.... ones good

Blub...Blub...Blub...Waaaaaaaaaaaaaaaaaa

or

ones bad...

Duff...Duff...Duff...Vvvrrrrrrrrrrrrrrrrrrrrrr

If on the other hand it sound Deep and Rumbley... check the Fuel pressure.

Goodluck.

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Hmmm...good point. The exhaust has a dual outlet muffler on the pax side, so kinda hard to hear. Other than that, on the road, the d@mn thing WON'T accelerate.

Like I said, I've about convinced myself that I just need to bite the bullet, hand over the wallet, and replace the whole exhaust & pull the tank.

Thx & keep the info coming!

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  • 3 weeks later...

Here's how to find out the problem....

Go to the Chevy dealer and speak nicely to the service writer, ask him is it atall possible can you use the TECH2 on my truck and see what I need to bring the truck in for..

If he's nice enough to do it, he will tell you what your computer is communicating about the problem..

You can only try, failing that drive around back and ask one of the techs for a few bucks can you tell me whats wrong......

I used to work at the Chevy dealership and they were friendly enough to do it for free, usually they want to charge .5 (30 mins labor)

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