5.7 TBI gas mileage and performance

[fiveseven z28 z71]

I just bought a 95 Sierra 1500 Z71 with a 5.7 TBI. It has about 96000 miles on it and runs great. I am wondering what can be done that can increase gas mileage and/or performance. I drive about 140 miles a day, so increased mpg would be nice. I am interested in hearing what anyone has to say about any mods they know of, whether they be aftermarket parts, mods to current parts or anything else.

[Rookie]

I hope you have a thick wallet. I have a 98 Yukon w/ 5.7 and I put a KNN filter on mine and wopuld say i picked up 2-3 mpg. i have found the magic number is 2000 rpms. If i go above that or 70mph i can watch the gauge fall.

[redvett]

Your PU truck will respond best to a hard tonneau cover. A steady speed with cruise control on will give you +5%. Keep your speed close to the speed limit and no jackrabbit starts. Works for me. My 01 4x4 Z71 got 18.8 to 19.5 and my 04 4x4 Z71 exact same truck gets 20 average.

[Mule]

As far as mods, look at the link in my signature for what I did to my 1995 Yukon (same engine). Not cheap though.

[Wingnut]

I just bought a 95 Sierra 1500 Z71 with a 5.7 TBI. It has about 96000 miles on it and runs great. I am wondering what can be done that can increase gas mileage and/or performance. I drive about 140 miles a day, so increased mpg would be nice. I am interested in hearing what anyone has to say about any mods they know of, whether they be aftermarket parts, mods to current parts or anything else.

First off...Welcome to the forum

 

What kind of MPG are you getting now? Gotta have a baseline before we can see if it can be improved.

 

My 92 gets around 15 MPG as long as I keep it under 75 on the highway. Only mods I have left are K&N drop-in, and cat-back flowmasters.

 

My 02 get's about the same.....If I pu$$y-foot it. But normally, I only get around 13 MPG. No mods except a drop-in K&N.

[SnakeEyeSS]

my truck would get 16 on 50/50 city highway, I'm guessing 18-20 100% highway. mads ar in link. 176K

[PeterbiltChrome]

free up your exhaust flow with a free-flow muffler or ditch the muffler all-together and put some chrome pipes on it! Less backpressure will let that engine breathe better and gives it a little better punch. It'll perform better and you won't make your foot ask it for more...but then again, once you hear the throaty small block you'll stomp it anyways~ thats the price for enjoing these thirsty powerhouses and i think its worth every cent.

[americanmuscleman]

I started adding parts to my 95' Tahoe's TBI 350 about 5 years ago. The engine didn't have enough torque to get me over hills in overdrive with 3.42 gears (runs 2000rpm at 78mph).

 

First I added an Fastchips chip (Stage II for 91 octane), cold air intake, and flowmaster exhaust. The combination picked up the power a little bit, but mostly just on the top end, and my shifts were now really firm from the chip which I didn't like.

 

Next I added all the mods in my sig in one shabang. It all added a lot more power all over the powerband. I can now take really good sized hills in overdrive now, and the midrange power is great. The downfall to it all is, it still doesn't have the really strong top end on it I hoped it would. The motor makes great torque though, as I pull a 4500lb ski boat regularly and it doesn't have any trouble. Another downfall is the gas mileage. I get about 11mpg in the city, and about 13 on the highway... but it sounds awesome and I look forward to starting it everyday!

 

If I were you, I wouldn't go crazy on performance parts on a TBI motor. You really won't see a great gain for your money.

[wisconsinz71]

 

 

I just bought a 95 Sierra 1500 Z71 with a 5.7 TBI. It has about 96000 miles on it and runs great. I am wondering what can be done that can increase gas mileage and/or performance. I drive about 140 miles a day, so increased mpg would be nice. I am interested in hearing what anyone has to say about any mods they know of, whether they be aftermarket parts, mods to current parts or anything else.

I had a 92 ext cab SB. I did about every simple bolt on I could come up with. Biggest ains were a K&N filter, a Flowmaster Force II cat back system and Dunlop Radial rovers. If kept under 65 it would pull 17 on the highway. Engine was original with 185K when I sold it.