Picked Up A Mint 1993 Yukon 2dr

hoorders · March 25, 2010

Hey everyone,

Im usually in the 'full size' section of the site but I have recently sold my 2000 silverado and picked up this amazing 93 yukon 2dr SLE. This thing has 112000 original kilometres, original paint. Been oil sprayed every year. I swear this truck could be put in a show room....its that clean inside and out.

I love it!!!

Anyways its got the 5.7 EFI and I was wondering if there are any mods I can do to improve the milage some?

I dont think its that much worse than my silverado with a 5.3 was on fuel but I wouldn't mind making some mods to get a bit better milage.

Does a throttle body spacer help?

Cold air intake?

The exhaust is brand new front to back and looks like a decent size diametre.....so not sure if I want to change this.

Does this model year have a programmable PCM??

Any suggestions would be greatly appreciated.

I will post some pics soon.

Thanks!!!.............

kuhl_530 · March 25, 2010

If by EFI you mean throttle body injection, then yes a throttle body spacer will help some. I have a 95 Sierra with a 5.7tbi and have tried every feesable attempt to improve my milage, just for the sake of it. I have a flowmaster exhaust, k&n cold air intake, and an msd ignition system. I have yet to try a throttle body spacer, but have toyed with the idea for some time. Some people say that spacers are a waste of money and don't work, but I suspect they've tried installing them on a direct fuel injection vehicle, lol.

In 93, vehicles had OBD I computer systems, which are not programmable. There is a guy out there who burns replacement computer chips for Chevy tbi trucks, but you have to have access to a laptop, download a data logger program, and purchase a cable that tethers your computer to the diagnostic port on your truck. If you're interested I can send you a link to his site.

Otherwise, your best bet for fuel economy is to open the intake and exhaust via vortec heads, cold air intake, headers and the exhaust you already have. None of them are completely necessary, but will help some. Same with a high output ignition system to get a more complete burn, therefore better economy. Also think about replacing all of your oils with synthetics. Synthetics have a lower pour point, so they offer less resistance when they're cold. Engine oil, trans and transfer case fluids (should be the same) and gear lube in the front and rear will make a little difference.

rodram · March 25, 2010

I answered your other post too.... my opinion is that your best investment to maintain gas mileage on this TBI will be a tune-up with new ACDelco plugs, new wires, new distributor cap, new air filter, and injector flush...

gregrocks89 · March 26, 2010

never touch a throttle body spacer. just a waste of time and money

johngmtech50 · March 26, 2010

Hey everyone,

Im usually in the 'full size' section of the site but I have recently sold my 2000 silverado and picked up this amazing 93 yukon 2dr SLE. This thing has 112000 original kilometres, original paint. Been oil sprayed every year. I swear this truck could be put in a show room....its that clean inside and out.

I love it!!!

Anyways its got the 5.7 EFI and I was wondering if there are any mods I can do to improve the milage some?

I dont think its that much worse than my silverado with a 5.3 was on fuel but I wouldn't mind making some mods to get a bit better milage.

Does a throttle body spacer help?

Cold air intake?

The exhaust is brand new front to back and looks like a decent size diametre.....so not sure if I want to change this.

Does this model year have a programmable PCM??

Any suggestions would be greatly appreciated.

I will post some pics soon.

Thanks!!!.............

hope i can help you in your quest for fuel mileage

i have been a gm tech for about 10 years ,there is no magic formula to this, i recommend the following.check the gear ratio.hope fully it is 373 or lower if they are 410/411 your done you will never get much more than you are getting now. so lets asume the best .start with a high flow air filter such as k&n brand being one of the best.dont waist the money on a cold air kit you won't see any benefit to it .your not building a tuner car.second,throttle spacers only work to getting very slight inprovement on exstreme top end of rpm and you won't even feal it ,so spend it on headers,low flow restriction exhaust system duals.3rd,proper tire inflation,every month check them.good front end alignment once a year! .4th syn oil in engine 100% not a blend oil. run 100% syn in all your drive line front to back including trans. this combo has gotten me a 5 to 7 mile to the gallon increase total average of 24 hwy/15city and remember it is a truck so to exspect good fuel mileage is not realistic but low 20's aint half bad and the power in crease will be well worth it when you leave a 75 foot strip with both tires smoldering!!! at the lights and see the look on that rice burners face as you leave his honda sitting there. hope this helps,good luck, john.

Wingnut · March 26, 2010

I had a '92 Chevy version of that truck for almost 10 years...And I can say that the BEST I ever got out of an average tank is 15mpg. It *might* do a tad better on the highway, but not much. I usually averaged closer to 14 mpg.

hoorders · March 28, 2010

Thanks for all your replies.

After replacing all the plugs, wires, cap and rotor im hoping it does a bit better. Some of the plugs were NASTY and the contact points under the rotor were looking pretty bad as well.

I will try and post some pics today.

Thanks!!

hoorders · March 28, 2010

Hey everyone,

Im usually in the 'full size' section of the site but I have recently sold my 2000 silverado and picked up this amazing 93 yukon 2dr SLE. This thing has 112000 original kilometres, original paint. Been oil sprayed every year. I swear this truck could be put in a show room....its that clean inside and out.

I love it!!!

Anyways its got the 5.7 EFI and I was wondering if there are any mods I can do to improve the milage some?

I dont think its that much worse than my silverado with a 5.3 was on fuel but I wouldn't mind making some mods to get a bit better milage.

Does a throttle body spacer help?

Cold air intake?

The exhaust is brand new front to back and looks like a decent size diametre.....so not sure if I want to change this.

Does this model year have a programmable PCM??

Any suggestions would be greatly appreciated.

I will post some pics soon.

Thanks!!!.............

hope i can help you in your quest for fuel mileage

i have been a gm tech for about 10 years ,there is no magic formula to this, i recommend the following.check the gear ratio.hope fully it is 373 or lower if they are 410/411 your done you will never get much more than you are getting now. so lets asume the best .start with a high flow air filter such as k&n brand being one of the best.dont waist the money on a cold air kit you won't see any benefit to it .your not building a tuner car.second,throttle spacers only work to getting very slight inprovement on exstreme top end of rpm and you won't even feal it ,so spend it on headers,low flow restriction exhaust system duals.3rd,proper tire inflation,every month check them.good front end alignment once a year! .4th syn oil in engine 100% not a blend oil. run 100% syn in all your drive line front to back including trans. this combo has gotten me a 5 to 7 mile to the gallon increase total average of 24 hwy/15city and remember it is a truck so to exspect good fuel mileage is not realistic but low 20's aint half bad and the power in crease will be well worth it when you leave a 75 foot strip with both tires smoldering!!! at the lights and see the look on that rice burners face as you leave his honda sitting there. hope this helps,good luck, john.

I checked the RPO codes and the gearing in my yukon is 342. I dont do much towing, so im gald it has 342 in it.

VRSCA1 · March 31, 2010

Hey everyone,

Im usually in the 'full size' section of the site but I have recently sold my 2000 silverado and picked up this amazing 93 yukon 2dr SLE. This thing has 112000 original kilometres, original paint. Been oil sprayed every year. I swear this truck could be put in a show room....its that clean inside and out.

I love it!!!

Anyways its got the 5.7 EFI and I was wondering if there are any mods I can do to improve the milage some?

I dont think its that much worse than my silverado with a 5.3 was on fuel but I wouldn't mind making some mods to get a bit better milage.

Does a throttle body spacer help?

Cold air intake?

The exhaust is brand new front to back and looks like a decent size diametre.....so not sure if I want to change this.

Does this model year have a programmable PCM??

Any suggestions would be greatly appreciated.

I will post some pics soon.

Thanks!!!.............

Due a tune up,check the ignition timing,air up the tires,change the air filter,then leave it alone if its as nice as you say it is then dont put any of that aftermarket crap on it,if you need fuel mileage buy a yugo.

just my 2 cents,If it ain't broke then don't fix it.