Gas Mileage

My 2000 Intrigue isn't getting near the gas mileage it should. I spent over $700 at the dealer last month to get a wheel sensor replaced, alignment, oil change and other minor adjustments. I really don't want to spend $$ having them look at it again. Any suggestions on what I can look for that might be causing the poor fuel economy?

What are you calling poor?? :rofl:

I live in a pretty flat area (california central valley) and get about 23 city, 27 highway. Have gotten as high as 30mpg on all freeway driving.
Chernobyl

My girlfriend only gets about 17 mpg/city and 26 mpg/highway with her 1999 Intrigue GL 3.5L. I think it is a little under par. I have heard that worn transmission fluid will cause more torque converter slippage thus decreasing gas mileage. I just checked her fluid and it is definitely worn with all of 92k miles on it. It is dark brown with almost no hint of red. Good tranmission fluid should look red or even pink. I'm going to change the tranmission filter and replace 7.4 qts. (amount lost with pan removal) of 10 qts. (total capacity) of fluid. I would say that you do the same and see what happens. I've been told to NOT get a flush done because this would do more harm than good. I've heard on this and other forums of many people having problems with their tranny after getting a flush done when they were in a similar situation.

I recently tried an oil additive and to my surprise, my gas mileage has gone up markedly. (Got 28MPG on my last two tanks - 75% Freeway, 25% City)

The additive is Valvoline Syntec (Synthetic oil additive in a silver bottle they sell at autozone). My engine is the 3800 so maybe it helped reduce the friction in the older-style pushrod motor. For a few bucks, why not give it a try and see if it works for you.

I have a 2000 Intrigue and I am getting 18 city and 26 hwy

My 2001 is getting about 23 (thats a good 50/50 mix of highway and city driving). In the winter that goes down to about 19.