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I've recently "inherited" a 1994 GMC Sierra K 1500. It has a 4.3L vortec 6 and manual transmission. 110k miles. Not a bad truck despite the fact that my father took very bad care of it. I've been sanding and painting it so that it doesn't look like a total beater. I like that it's a 4X4 since I do a lot of outdoors recreation. Eventually (when I get some money) I'd like to put in some lifts and bigger tires.... BUT... it has no power. On level ground it's fine the 4wd has gotten me out of the ditch more than once. but as soon as I run into a hill when I'm on the highway I start losing speed very quickly and have to downshift everytime, on very steep hills sometimes I have to go to 3rd even. I'm afraid I'm going to start getting nasty speeding tickets for running at the base of hills at top speed to make it to the top =) My theory is that the cheap muffler my father put on it is choking the life out, though, I'm beginning to wonder if I should just say to hell with it and wait till I can afford something with a V8.

Anyway I was wondering if anyone had some advice for me to give this thing a little more ummph so that I can visit my friends who live uphill from here. I'm on a very tight budget and not much of a gearhead so I'm looking for cheap solutions. I've read some of the other articles about 4.3L trucks and they were very informative but I'm wonding which are the best for a poor person like myself. for example will a K&N filter and new exhaust add enough power to be worth the cost with a smaller engine like this?

Thanks!
 

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Discussion Starter #3
Right now everything is stock. Just your typical generic K1500 Longbed as far as I know. cheap 8ply tires 225 on 17inch rims i'd guess. I don't do anything stupid with it like run around in 4wd low gear. I keep in in 2wd High pretty much unless I've gotten myself stuck someplace or am planning to. The only modification if it even qualifies are the God-awful gabriel air shocks in the back he put in so it didn't bottom out with an ulta heavy load.
 

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I was just wondering cause if you had on bigger or heavy tires it could be whats dragging you down on hills. Also i dunno if they did offer 3.08 gears back then but if thats what you have then that would explain a thing or two.
 

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theres another member on mychevytruck.com who has the 4.3L with 35's and a lift. Intake and exhaust, and i guess it has decent power. i would just put a few bolt-ons, way cheaper then a new vehical
 

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Discussion Starter #7
Whifflebat said:
What part of iowa?

Sounds to me like lower gears would be helpful.
Probably, but probably not cheap or easy either. That's what I'm lookin for. I think a few simple bolt-on's are my best bet but I'm wondering which will give the best bang for my buck. (and the ones i'm least likely to screw up) :drool:

I'm from the Ames / Des Moines area.. movin out of Ames to Des Moines right now. New job which means I'll have money for big toys but I'm still eating Ramen for the time being :insane:
 

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http://www.gmfullsize.com/forum/showthread.php?t=877

That might help you a little.

As for seeing what gears you have Look in the glovebox at the RPO codes and see what gears you have:

G80 is the eaton locker (posi)

GU4 -- AXLE REAR, 3.08 RATIO
GU5 -- AXLE REAR, 3.23 RATIO
GU6 -- AXLE REAR, 3.42 RATIO
GT4 -- AXLE REAR, 3.73 RATIO
GT5 -- AXLE REAR, 4.10 RATIO
HC4 -- AXLE REAR, 4.56 RATIO
 

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Discussion Starter #10
OK, for some reason I couldn't find that before but it was in plain sight, go figure. It's a 3.73 ratio.
 

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Could be just a tired motor. I know my 4.3 halfton (stepside though) would really cook for what it was...most people thought it had a 305. I rolled it doing 110 (up a hill, hehe). Nothing close to my l31, but respectable.

Give it a serious tuneup. New plugs, wires, pcv valves, etc. Clean out the vacuum system. A good cleaning makes a huge difference on the tbi systems, especially if they were lugged around in higher gears all their life. With the 3.73's I could throw around some smoke running on 265's and 285's.
 

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The vortec 4.3 (NOT the TBI 4.3 :read:) is quite powerful. I had a buddy do a nice non-power brake burn out with his 4.3, I was impressed. I think it was pretty close to the 305 for power too.

Has it mechanically been taken care of? From what I gather the body was neglected which would make me guess that it was mechanically too. As previous said, do a full tune up on it. Cap, rotor, PCV, plugs, fuel filter, air filter, etc.

Also, too small of a muffler can choke it a little.
 

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Thanks guys,

It is the vortec 4.3L. and it is generally pretty powerful, I've never had trouble spinning the wheels, heck sometimes I do it accidentally when I haven't been driving a stick in a while :) It only seems to have trouble when going up a hill on the highway. I replaced the air filter a while back and that made a big difference, God, I think I pulled something like a dead cat and the bird it was chasing out of that thing.

Aside from that I think he had it in for a bunch of work about 15K miles ago new plugs etc, (still trying to figure out what the shop abbreviations all are) Knowing my father, that was probably the first time he took it in, 8 years and 95K miles!!! that says a lot for how tough these machines are!

Judging by the wheezing suffocated like noise the engine makes I'm guessing that the muffler has a lot to do with it but the other suggestions people have made; cap, rotor, pcv, wires, fuel filter all deserve looking into too.

I'm thinking about putting in a cat back exhaust once I get the rest of the thing in better shape. Any suggestions on a cheap but respectable system?
 
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