I have a 1997 4-door blazer and it has a brand new 4.3L engine in it with an 18 gal tank. The problem is that I'm getting lass then 200 miles to a tank. It fills up with 17 gal so I know the gauge isn't broken and I currently can't get it into 4x4 because I'm waiting to get a new tccm. There is also no gas smell.

Any Ideas why the MPG is so low? What is everyone else getting?

 

crappy city(13-15) highway around 18-22 but I've got a misfire on cyl 2 and my sel flashes at low rpm under load ever since I hydrolocked my motor(oops I JUST took my foot of the gas when i sucked the water/mud in so i guess it could have been worse)


vacuum leak can cause bad milage. does it run good or miss or anything? spray intake cleaner on any cracked lines and connections and see if it changes your rpm

clean ur maf, egr, throttle body if it's not new

there is a lot more that can go wrong then just the tccm if you didn't diagnose it first. a vac leak can cause front axle to not engage.

who put the motor in? did you or whoever miss a vacum line or 2? does your heater vents move to the desired location properly and stay there at all rpms?


could just be the motor needs to break in still(rings, etc might not be completely seated yet)

 

How do you drive? Where do you drive? there is more to MPG than just an engine, it could be you do a lot of hilly driving.... there is also if you drive solely city you will get less than on the highway...

 

WLorton- I live at the beach (no hills) and we only really have 2 highways (55/60 and 45/50 speed limits) to get anywhere. Even though there are a few lights, it is the off season here and I only take it to work 15 miles away and I usually get there in 15 min.

69chevelle- sorry to hear about the Hydrolock... I did that to my Jeep once.
It runs great! actually better then either of my 2 buddys' blazers of similar year. It never misses and has surprising quick acceleration. It doesn't idle high or low at any time... though It did stall once when running cold and shifting from R to D.

My mechanic installed the engine. He's pretty good and has taken care of all my cars' big jobs (I don't have a lift) for the last 15 years and has never mess up. But I will double check all of the vac lines. The heat works through all settings and RPM that I drive on a daily basis (no red lining). I only have 500mile on the new engine so I hope your right about just breaking it in.

I'm not sure what egr is but I'll clean the rest tomorrow.

I'm pretty sure that it is the tccm. I pulled it out and put in my buddies and it worked fine for about 15 min before I gave it back to him.

Thanks for the help and if you think of any think else I would appreciate hearing it.

 

does your truck have enough time to warm up? haha, I know my torque converter wont lock untill my tranny hits a certain temp, and that happens basically as I get to work, which is about 15 min away.

did you get better milage before the swap?