gas mileage problem?

rx7turbo2 · 03-09-2006, 10:03 PM

i have a 99 blazer, 4x4, and i have been getting an average of 12.5 mpg in town with a little bit of highway driving mixed in. this seems like a terible figure, even for a blazer. i dont get on it very much, even with the cruise set at 60 on a level road the computer reads like 16-18 mpg. seems like others do better than me. anyhting i can check? runs good, no hesitaiton or roughness. no check engine light, if i remember from my last s-10 (91 4x4 ext cab 4.3) the bad o2 sensor threw a code on it. my mom's identical 2001 jimmy (same miles 60,000, same equipment) gets 2 or 3 better mpg on average. help me, im pissed. thank you.

Xourque · 03-09-2006, 10:43 PM

Quote: Originally Posted by rx7turbo2

i have a 99 blazer, 4x4, and i have been getting an average of 12.5 mpg in town with a little bit of highway driving mixed in. this seems like a terible figure, even for a blazer. i dont get on it very much, even with the cruise set at 60 on a level road the computer reads like 16-18 mpg. seems like others do better than me. anyhting i can check? runs good, no hesitaiton or roughness. no check engine light, if i remember from my last s-10 (91 4x4 ext cab 4.3) the bad o2 sensor threw a code on it. my mom's identical 2001 jimmy (same miles 60,000, same equipment) gets 2 or 3 better mpg on average. help me, im pissed. thank you.

I have a 1998 Jimmy that recently started getting bad mileage as you described. I did not find a specific thing wrong with it, however, after doing the following it got better:

1) Rotated the tires and made sure the tire pressure was at the factory specs.
2) Got a new air filter. (i'd reccomend getting a K&N stock drop-in filter)
3) Did an engine oil flush.
4) Did a transmission fluid flush.
5) Changed the transfer case, front diff, and rear diff fluids.
6) New ACDelco Plat plugs (only use ACDelco!)
7) New Autolite plug wires
8) New Autolite cap and rotor

Now it cruises down I5 at about 75, and the engine computer reads ~19-21mpg.

Xourque · 03-09-2006, 10:45 PM

Also, I should mention that the spark plugs, wires, cap+rotor, and the O2 sensors don't need to be changed until 100,000 miles.

ace16a · 03-10-2006, 12:09 AM

I get 25 mpg on highway with my 96 4-door blazer. I have a custom cold air kit with a k&n cone filter. I also recently changed spark plugs, wires, cap, and rotor. I noticed the biggest change when I replaced all 3 O2 sensors.

ace16a · 03-10-2006, 12:11 AM

Oh, FYI. I use Bosch platinum spark plugs, Accel wires, Accel cap and rotor, and Bosch O2 sensors.

j894 · 03-10-2006, 05:09 PM

was you truck throwing codes for the 02s b4 u chaged them?
Just curious

rx7turbo2 · 03-10-2006, 06:19 PM

well, i wouldnt think my truck would be due for a tune-up yet (with 60000 miles on it) perhaps the cat might be partially plugged? is there a way to test the cat?

juddspaintballs · 03-23-2006, 08:57 PM

i'm gettin about 22mpg with a high flow exhaust and AEM cone filter on custom intake tubing. i change my fuel filter, distributor cap/rotor regularly as well as my oil. i could prolly use new sparks and wires this summer. changed the O2 sensors on the Y tube last winter. i got my biggest increase in gas milage with the $109 exhaust from summit racing.

Insane 95 Blazer · 03-31-2006, 02:38 AM

AC Delco or NGK because they burn a bit hotter than stock AC . Autolite Wires really are not good wires . Belden makes a decent wire but I would rather have Delco Wires or MSD wires like I have on my 95 Blazer . I have been running NGK iridiums in my blazer but am going to switch back to AC Delco Rapid Fire . Just got my new MSD Cap & Rotor kit for the vertical tower distributors .

03-09-2006, 10:03 PM	#1
rx7turbo2 Registered User Age: 30 Join Date: Aug 2005 Posts: 21 Location: User is: OffLine	gas mileage problem? i have a 99 blazer, 4x4, and i have been getting an average of 12.5 mpg in town with a little bit of highway driving mixed in. this seems like a terible figure, even for a blazer. i dont get on it very much, even with the cruise set at 60 on a level road the computer reads like 16-18 mpg. seems like others do better than me. anyhting i can check? runs good, no hesitaiton or roughness. no check engine light, if i remember from my last s-10 (91 4x4 ext cab 4.3) the bad o2 sensor threw a code on it. my mom's identical 2001 jimmy (same miles 60,000, same equipment) gets 2 or 3 better mpg on average. help me, im pissed. thank you.
	[Reply w/Quote]

03-09-2006, 10:43 PM	#2
Xourque Registered User Age: 25 Join Date: Sep 2005 Posts: 111 Location: Seattle, WA User is: OffLine	Re: gas mileage problem? Quote: Originally Posted by rx7turbo2 i have a 99 blazer, 4x4, and i have been getting an average of 12.5 mpg in town with a little bit of highway driving mixed in. this seems like a terible figure, even for a blazer. i dont get on it very much, even with the cruise set at 60 on a level road the computer reads like 16-18 mpg. seems like others do better than me. anyhting i can check? runs good, no hesitaiton or roughness. no check engine light, if i remember from my last s-10 (91 4x4 ext cab 4.3) the bad o2 sensor threw a code on it. my mom's identical 2001 jimmy (same miles 60,000, same equipment) gets 2 or 3 better mpg on average. help me, im pissed. thank you. I have a 1998 Jimmy that recently started getting bad mileage as you described. I did not find a specific thing wrong with it, however, after doing the following it got better: 1) Rotated the tires and made sure the tire pressure was at the factory specs. 2) Got a new air filter. (i'd reccomend getting a K&N stock drop-in filter) 3) Did an engine oil flush. 4) Did a transmission fluid flush. 5) Changed the transfer case, front diff, and rear diff fluids. 6) New ACDelco Plat plugs (only use ACDelco!) 7) New Autolite plug wires 8) New Autolite cap and rotor Now it cruises down I5 at about 75, and the engine computer reads ~19-21mpg.
	[Reply w/Quote]

03-09-2006, 10:45 PM	#3
Xourque Registered User Age: 25 Join Date: Sep 2005 Posts: 111 Location: Seattle, WA User is: OffLine	Re: gas mileage problem? Also, I should mention that the spark plugs, wires, cap+rotor, and the O2 sensors don't need to be changed until 100,000 miles.
	[Reply w/Quote]

03-10-2006, 12:09 AM	#4
ace16a Registered User Age: 29 Join Date: Dec 2005 Posts: 25 Location: User is: OffLine	Re: gas mileage problem? I get 25 mpg on highway with my 96 4-door blazer. I have a custom cold air kit with a k&n cone filter. I also recently changed spark plugs, wires, cap, and rotor. I noticed the biggest change when I replaced all 3 O2 sensors.
	[Reply w/Quote]

03-10-2006, 12:11 AM	#5
ace16a Registered User Age: 29 Join Date: Dec 2005 Posts: 25 Location: User is: OffLine	Re: gas mileage problem? Oh, FYI. I use Bosch platinum spark plugs, Accel wires, Accel cap and rotor, and Bosch O2 sensors.
	[Reply w/Quote]

03-10-2006, 05:09 PM	#6
j894 Unregistered User Age: 23 Join Date: Mar 2004 Posts: 3,532 Location: (on vacation) User is: OffLine	Re: gas mileage problem? was you truck throwing codes for the 02s b4 u chaged them? Just curious
	[Reply w/Quote]

03-10-2006, 06:19 PM	#7
rx7turbo2 Registered User Age: 30 Join Date: Aug 2005 Posts: 21 Location: User is: OffLine	Re: gas mileage problem? well, i wouldnt think my truck would be due for a tune-up yet (with 60000 miles on it) perhaps the cat might be partially plugged? is there a way to test the cat?
	[Reply w/Quote]

03-23-2006, 08:57 PM	#8
juddspaintballs I pee standing Age: 24 Join Date: Dec 2004 Posts: 6,098 Location: Union Bridge, MD User is: OffLine	Re: gas mileage problem? i'm gettin about 22mpg with a high flow exhaust and AEM cone filter on custom intake tubing. i change my fuel filter, distributor cap/rotor regularly as well as my oil. i could prolly use new sparks and wires this summer. changed the O2 sensors on the Y tube last winter. i got my biggest increase in gas milage with the $109 exhaust from summit racing.
	[Reply w/Quote]

03-31-2006, 02:38 AM	#9
Insane 95 Blazer Insane Bowties Join Date: Mar 2006 Posts: 8 Location: South San Jose User is: OffLine	Re: gas mileage problem? AC Delco or NGK because they burn a bit hotter than stock AC . Autolite Wires really are not good wires . Belden makes a decent wire but I would rather have Delco Wires or MSD wires like I have on my 95 Blazer . I have been running NGK iridiums in my blazer but am going to switch back to AC Delco Rapid Fire . Just got my new MSD Cap & Rotor kit for the vertical tower distributors .
	[Reply w/Quote]