Slow Drop in Gas Mileage

[1996xlt]

Has been dropping slowing over the past couple months. Just had the P0153 code and replaced the O2 sensor (factory) I suspect the cat is on its way out threw the P0420 (I think) code a couple months back but went away. I want to go ahead and replace it but don't want to shell out a couple hundred dollars to get a OEM one so what is everybody's thought on this: http://cgi.ebay.com/ebaymotors/MAGN...091187629QQcategoryZ33629QQrdZ1QQcmdZViewItem
Thanks in advance!

 

[nolimitssjca]

My mileage dropped over the years. I replaced all the o2 sensors after a o2 code made me fail emissions. Then my truck began to run rough and I replaced the EFI. They were a mess! The rail was relly dirty and I cleaned it out too. Afterreplacing the EFI I saw about a 70 mile range improvement in each tank. I figured @ $.20 mile, I was saving about $14/tank. It won't take long to make it back. http://www.accurateis.com/spray_testing_01.php There are place that refurbish you injectors so yuo can save some serious money if you decide to go that route.

You may want to clean your throttle body (easy to do) your MAF and change your plugs.