Afternoon,

Over the last month, I've replaced my distributor with an aluminum one (that has the brass contacts cap and rotor....) and replaced the spark plugs and wires. Cleaned the MAF sensor. I always run a can or two of Berryman once a month. At idle in drive, I still get a little stumble here and there. My fuel mileage is also still poor.....only 13-14 mpg. My question is, how much does the later MPFI fuel spider help with mileage and smooth running? If I'm gonna keep getting 13-14 mpg, I mozzle buy an older full size V8 pickup and have more fun! I junkyard frequently so they're easy for me to get. My rig is a California vehicle..............any difference in ECU calibration? I feel like other Federal Blazers I've rode in or drove had more power and got better fuel economy. TIA.

 

I think it's fair to say that these vehicles have poor fuel mileage. There is a thread here where people report their fuel mileage: https://blazerforum.com/forum/genera...pg-poll-18999/

For me, I feel like the MPFI upgrade caused the engine to run more smooth, but I did not notice any change in fuel mileage. That's not to say that it didn't improve the fuel mileage, and likewise it did not necessarily cause the engine to run more smooth.

I cleaned the MAF filter, throttle body, intake manifold and sensors I replaced the spark plugs, wires, rotor, distributor cap, clutch fan, and upgraded to the MPFI spider. At this point I feel like my vehicle's fuel mileage is approaching it's best: about 14 mpg all city driving in the summer.

Remember that the size of tires and type of rear differential will also impact fuel mileage.

 

When I upgraded mine I didn't notice a change. The reason I did the swap was because I already had the intake off to replace the gaskets and was able to find a new injector unit to install. I had heard that it might give better fuel economy, but I think any improvement was swamped by other factors like changing tires and carrying more supplies.

These will never be very fuel efficient vehicles, especially the 4dr, 4wd ones.

From what I remember, the only Blazers that were advertised to get mileage in the lower 20s mpg were the 2wd, 2dr ones with high ratio differentials. In contrast mine has the lowest ratio diffs which is fine because I use mine to tow a boat.

 

Thanks. Yeah, guess she's just an oinker no matter what. I'm always 13-14mpg whether I'm nice to her or not. Mixed driving. Sure wouldn't mind a smoother running rig, but the intake gaskets have already been done so there's no immediate need to open it up right now I guess. FWIW mine is all stock with 3.42 gears, and P235/75R15 Wrangler Trail Runner A/T's. No extra weight anywhere. No cat, but the light is off due to the anti-fouler trick until I can afford a y-pipe and new exhaust.

 

I'd have loved one of those 2 door 2wd flavors, but being in Michigan and having a family, I needed the 4 door four-by rig. Being a clean California princess, I couldn't pass her up anyway

 

I have been getting 14 mpg in town on my 2001 4-door 4x4 Blazer for over 10 years. I have a 6500# 4x4 2004 Avalanche (think Suburban) with 5.3 V8 that gets 17 doing the same driving on same routes. The Blazer is simply a gas hog - everyone's 4x4 Blazer is! Lucky to get 17 on the Interstate.

 

I get 17 on my 2wd so 14 seems reasonable for a 4x4.

George

 

Oh wow. Guess mine's average then. I used to have a 2006 Silverado with a 4.3....it was a 2wd, long bed 5 speed. And even that got better mileage. I suppose I figured the Blazer to be about even. Oops.....

 

My 2006 Sierra 1500 2wd gets 16

George

 

wow lots of action on this subject..lol,,my 2001 jimmy 15 MPG,,did the intakes on grandson's 1998 jimmy,200,000 + miles didn't bother to change out the spider,runs fine and goes everyday