2002 TB 2WD mileage sucks

bradrx7 · May 23, 2002

I've got about 3500 miles on my 2002 LTZ TB 2WD. My in-town mileage is about 10-10.5mpg and I have to drive like a sissy to get that. If I drive in the least aggressive, it plummets to 9.5mpg. Went to my stealer today, they checked the OMB2 for codes ... nada. What kind of mileage do you guys get? I get better mileage towing my race car (5000lbs. with trailer) than I do tip-toeing around the streets of Houston. If I had known this, I would've bought a V10 Excursion for a tow car. I have a friend who has one and gets 14mpg in the city. I'm pissed.

02EnvoySLT · May 23, 2002

4WD 02 Envoy

4.10's

7K on the odo

15.5mpg reported by the DIC

Mostly city driving...

Usually see about 260miles to a 16.x gallon full refill...

I remember only getting 13mpg when I had less mileage

Next time you refill, reset the trip and refill and note how many gallons you put in

inginear · May 23, 2002

Mine gets 18-19 mostly highway driving tho. Got over 17 pulling my pop-up camper.

stevieray36 · May 24, 2002

I have about 7K on mine and get 17.1 on the DIC. Thats in town and highway, about 75% highway miles.

drew · May 24, 2002

Something can't be right, that is way too low. I have a 2002 TB LT, 4.10, 4WD, and I get about 16, 75% suberb driving. Are you basing those values off of calculations or the computer, something can't be right?

bradrx7 · May 24, 2002

Thanks for all the replies...

You are correct, my truck if FUBAR. I checked mileage with the OBC, resetting it after fill up. I typically use about 16.5 gallons per fill up and get 170 miles in town. This is flat Houston, too and all side streets. I've checked my mileage manually and with the computer and they are very close and at 10.5mpg or so

Again, I went to the stealer and had the OBD2 checked for errors. I spoke with them today and they are stumped..

If I had known this was gonna happen, I would've bought a Suburban.

Frank S · May 24, 2002

Well,it's not always the case but here's something to try.

You have 3500 miles on your TB right now so keep track of the mileage and compare it again at 7k and 10k to see if it's getting any better.

There's no good reason for it to be getting that bad of gas mileage but it may get better after it breaks in a little more.

bradrx7 · May 25, 2002

Thanks, matter of fact I am keeping a log. If the mileage doesn't get better and the dealer cannot fix the problem, I will use this to get Chevy to buy back the POS under the Lemon Law.

I like the TB fine, but as I mentioned, I would prefer a larger truck if I am getting lousy mileage. The only reason I bought the smaller truck was for daily driving economy and that is one thing I am NOT getting.

inginear · May 26, 2002

Seeing the other thread on engine operating temperature, made me wonder what temperature is yours running? 210 deg, or something less? If less, then that may be the cause of the problem. Engine may be running a rich mixture because it thinks it's still cold, OR it may actualy be running cold.

02EnvoySLT · May 29, 2002

Just put in 15.5 gals to fill it up (Mobil 93 octane) and the DIC estimated 296 miles. We'll see what the actual ends up being. It was consitantly at 260-270 before this tank.

However, I did just run this last tank with the air box cut up and modded and a conical K&N filter on it. The throttle response is definitely better, we'll see what happens to the gas mileage long term.

Check the basics, make sure your induction system isn't plugged up, check the plugs, etc. Have someone scan it and log it with a tool like Autotap (www.autotap.com) and check and see what the running Ltrims are etc. Since we don't have a MAF based system, these things aren't going to be the friendliest with drastic induction/exhaust changes.

Try running 93 octane for a few tank loads. I don't know if these PCM have a Low and High Octane tables, etc like the V8's but you may be in Low octane mode from a bad tank of gas or may have overactive knock sensors, etc.

Just some thoughts... good luck.

bradrx7 · May 30, 2002

Thanks for all the tips.

I've worked through many of those already.

I've run some tests and it seems to be the initial throttle tip-in and during the idle circuit where I am gulping fuel. I use a different dealer than the one that sold me the vehicle, so I called my (wonderful) salesman and he contacted the service manager who left me a very nice message today concerning the mileage. he asked me to bring it in for a full round of checks with a loaner car. I had told my sales guy that I was interested in getting another vehicle to replace the TB if that was my expected mileage. I report what they find.

Thanks again everyone.