Anything else I should try?
 

I have a 2001 Venture with 153,000 miles. I have noticed that my mileage is getting really bad so I changed the plugs and wires, and cleaned the throttle body but it seems the mileage is still not very good. Anything else anyone can think of to do to help?

Air filter is important. Are there any check engine lights which could point to the right area. O2 sensors, MAF sensor, etc.

Sorry air filter was replaced..no there are not any check engine light on. The motor seems to run very good..just seems to be getting crappy mileage over the last year or so. Just did not know if there was anything else I could try to make it better.

Try this on youtube. It might help Auto Repair & Diagnostics : How to Diagnose an Engine Problem - YouTube

Other than that you probably will have to take it in to a shop and have a computer diagnosis.

Replace your O2 sensors and you will see a big difference in your gas millage. O2 sensors usually wont trip a CEL unless they are affecting another system.

Replaced mine last month when gas went 4.00 and just driving around town my wife gets another 50 or 60 miles to the tank... All she ever drives is in the city so I have never checked the hwy miles on my 97.

What is really bad mileage? What was it before? Check your tire pressure. Try replacing the t-stat. Other then that you need some specific testing done.

We used to get 400+ miles..now we are lucky if we get a little over 300. This vehicle is used primarily in town, but gets used a couple times for our daughters softball tournaments. We notice that once it gets below a half tank it seems to use more gas then when it is over a half tank.

I will replace the o2 sensors..see if that does anything.

The gas gauges are set up to go slowly from full to half and then quickly from half to empty. Mine does that also. I guess they think they are making you think that nyou are getting better gas mileage than you really are.

Maybe off the note, but my Venture consumption is about:
22 mpg in summer and 19.6 mpg in winter time, which takes me up to 500 miles with a full tank depending on weather and driving style...

300 miles per tank seems to be quite low number. Not sure which version of Venture you have, mine is LS with 25 gal tank.