I think the EGR light comes on based on the mielage to remind you to check the EGR system, not to indicate a problem with it.

The EPA listed your rig as 15 city / 17 hwy when it was brand new... 20 years ago! You can probably do some things to boost your mpg - I'd definitely do the carb - but you'd be hard pressed to get over 20 mpg city. IMHO the less than stellar fuel economy is totally worth it when you consider all of the other good things about these trucks. Good luck with whatever you decide to do with it <img src="/forums/images/graemlins/cheers.gif" alt="" />