Hey all,

I have a 1993 C2500, which I dont tow with, dont really race and dont do to much other than drive to school and work. I get like 10 miles to the gallon and I was wondering, will a 4.3L V6 bolt into my rig with out to many mods? Its got the 5.7 in it now. Thanks

 

I had the 5.7L and I got 15mpg in the city with my C1500. You can do mods to those engines to help mpg.

 

A 4.3 V6 would probably get worse mileage in your truck. Do the basic things to improve mileage. Are the plugs and wires good, fuel filter, exhaust oxygen sensors, etc? The cats suck on those things to. You might consider a hi flow unit if possible.

 

I agree that you may get worse mileage with the 4.3. Swap gears. That 2500 may have 4.10's in it. go with some 3.36's or 3.08's. Also contact Brian Harris @ www.tbichips.com. he can tune you a gas mileage chip and also give you the info for recalibrating your DRAC module (speedometer control module) if you swap gears. Tell him Mark Howard sent you.

 

I agree...a 4.3L just don't have the torque to move these trucks as easy as a 5.7L. Oh, my 15mpg were with 3.73s.....3.42's would be a better choice with stock wheels/tires for the highway.

 

Thanks guys,

My dad said the same thing, that a 4.3 would have to work more to move that beast. I did a complete tune up, plugs, wires, cap, rotor, air filter, flushed all the fluids and greased her up. I put accell wires, plugs and cap and I ahve a flowmaster exhaust, would changing the o2 sensors do anything for me?

 

Did you change the fuel filter? If you didn't, change that, the TBI engine is senitive to fuel changes. Changing the 02s would give the computer more accurate readings b/c they are newer verses your older 02s. Changing gear ratio in the rear end would be the best thing for mpg. A high flow cat would help the engine to exhaust better. Also, when you did the tuneup, did you put a rotor button on the distributor as well?

 

ya I did the button when it was apart, I'm gunna replace the fuel filter today since I forgot about it. Thanks guys

 

My 95 TBI always responds well to a fuel filter change. Even in as short a time as 40k miles. Throttle response and mpg always was better. If the O2's have never been changed, I would definately put that in your budjet. They tend to get lazy as they get older and don't respond very fast and aren't as accurate.

 

Heres one for you,

I can drive the truck fine when I run it normaly, then when I plant the throttle its "chuggs", it physicly sounds like I'm hitting the rev limiter and doesnt want to go. SO.... I think my fuel filter might be plugged, like the motors not getting enough gas. Also on the same note, some times, maybe once a month when I go to start her after its warm the motor will start and then shut down, in order to keep it running I have to give it some gas? Its wierd but it sounds like it could be a fuel filter. Thanks again guys