Gas mileage - 98 2 door tahoe

[hawkeyedh]

I just purchased a REALLY nice ’98 2 door tahoe. It replaced my ’99 4 dr. My ’99 was pulling 13-14city/15-18 hwy. The new truck is only getting 11-12mpg in town. It runs great (I’m a shade tree mechanic and I’m ANAL about how my vehicles run). I just had emissions done on it and it passed with flying colors. My temp gauge was reading very low, so I just replaced the tstat and the temp sender for the computer. It looks like the sender for the gauge was the cause of the gauge reading low (I'll know for sure when I replace it tomorrow). I was hoping that it was actually running very cool – hence the bad mileage.

What else can I check on this? I was thinking that the e-test kind of rules out the o2 sensors, but who knows. I was also thinking that a bad 02 sensor would set the check engine light off. any mechanics out there?

 

[bparker]

Not sure about your problems, but I wanted to say congrats on your new hoe and also I am surprised as my 96 2dr hoe got better gas millage than my 02 4dr did in the past. And WAY better than my Escalade is getting :lol:

If I were to make an over all suggestion is to free up the intake air flow (air intake, ported TB) and then free up the exhaust (headers, free flow cats and exhaust) and you should see much better numbers.

In any case, let us know what you find. I am interested as well.

 

[hawkeyedh]

Rather than taking the conventional approach and band-aid the problem(bolting on aftermarket parts), I'd rather just fix the actual problem.

I'm wondering of the MFI conversion would help with this? I replaced the spider in my old truck and it really did run alot better when I was done. I hate to mess with this truck since its running so good, but I need better mileage. No mechanics out there?

 

[Mike97]

You should be getting a little better mileage than that, but not by much. What are you getting for highway mileage? I average about 15 mpg with a mixture of about 70% highway/30% city in my 97 2 door. The best I've ever gotten was 17 mpg, all highway.

A bad o2 sensor would definitely throw a cel. Are the tires and wheels stock size, or oversized. I know that you said it's running good right now, and just passed emissions, but when was the last tune-up performed? What temperature thermostat did you install?