11-12 mpg

[2bbows]

I just resently picked up a 99 jimmy 4.3 is 11-12 mpg in the city, normal just seemed a little low to me. thanks
mike

[4x4 blazerguy]

Yea I'd say way too low. Heck I get 9-11 MPG out of my 1986 Ford F250 4x4 with a 460 in it.
Our 97 Blazer 4x4 4.3 gets 20-22 MPG. Our 98 Jeep Grand Cherokee 5.9 Limited gets 14-18 MPG.
Are you getting any codes? I would start with checking plugs, wires, & fuel leaks.

[2bbows]

Right after I got it about 1 month ago I put in new plugs, checked the wires, new fuel and air filter, no change in mileage. No codes thanks
mike

[Leeann94astro]

What temp is it running?

[2bbows]

It is running in the 200-210 range

[Leeann94astro]

Okay, then.

When you replaced the plugs, how did they look? Were they coffee-colored, black, white, what color?

Also, have you checked your cap & rotor?

[Rick Norwood]

Originally Posted by 2bbows

I just resently picked up a 99 jimmy 4.3 is 11-12 mpg in the city, normal just seemed a little low to me. thanks
mike

You should be seeing at least 16-18 MPG in the city. Start with the basics. Before you throw a ton of cash at it, you might consider a diagnostic check at a reputable garage, maybe one with an Emissions or Exhaust Analyzer. You could be dumping huge amounts of unburned Gasoline into your exhaust system.

I would also check for vacuum leaks, missing or rotted vacuum lines and hoses, PCV Valve, and maybe a little fuel system cleaner.

Since the Plugs are done, Spark Plug Wires, Distributor cap and Rotor would be my next thought. After that, Oxygen Sensors.

[2bbows]

The Plugs that came out all looked really good, the plugs that came out were like a platium plug with the small pionted electord the one the local parts gave me for replacements were just standard plugs, I would not think that would make that much differance. I have not checked the cap and rotor yet, I guess that will be the next step, we do not have smog testing around here, but I do have access to a scanner, is there somewhere I can look to see what the readings should be. It idle and runs great and only has 80K. thanks
Mike

[4x4 blazerguy]

If you did not go back with the platinum plugs AC Delco are highly recommended by most of the guys I know running Blazers then that could be a lot of your problems.

[2bbows]

Ok, thanks I will change the plugs this weekend and check the cap and rotor. Is there a place on line that I can lookup the readings ranges that should be if I get a chance to hook a scanner up? thanks
mike

[4x4 blazerguy]

I can't help you with any reading ranges. The reason I say the plugs is the OEM plug for your Blazer was a Platinum AC DELCO Plug.

[2bbows]

well got the plugs, cap and rotor changed, cap and rotor needed it so donnt fell like a waste of time or money, will see if things improve. thanks for the help so far.
mike