I am having the some of the same problems with my 98. I started off with a T-code P1171 which was running lean under accel. I am about to change my filter this weekend and see if that is the problem. I noticed a decrease in MPG and loss of power as well. I thought it was my air filter (open cone filter) which was really dirty. I cleaned the filter, MAF, and EGR valve. I then cleared the code and so far it hasn't appeared. I now have ordered a diagnostic tool to help me targeting the problem. I can't keep taking my rig into the shop. I'll let you know once the scan tool is in place and what the diagnosis is. <img src="/forums/images/graemlins/kewl.gif" alt="" />