95 350 TBI power problems? MERLIN help!!!

My 95 Z71 has recently began to give me some trouble. The truck has 136,000 miles and has been trouble free its entire life. Over the past month the truck has started to become more difficult to start. The truck cranks over a lot more before actually starting. After it has run it does not take as much cranking though. It drives great around town and idles fine but when I get to a hill it does not have the pulling power it had a few months ago. Mileage has not seemed to change. My first impression is a fuel problem. I am going to change the filter and see if this helps. Can anymore give me more ideas or troubleshooting tips to help me fix this problem? The truck has been maintained well over its life and I have changed the fuel filter a few times, not sure how long since the last time. If the filter idea doesnt work, what other methods can I turn to? Could it be the fuel pump? or ignition? HELP!

Well, I would check fuel pressure......should be between 9-14 psi..I like to see around 11-12..
I have seen some of those engines with the same problem you have described..when I checked the fuel pressure it was running around 7-9 psi...cold, the engine was very difficult to start and had little or no power while driving..would idle fine when warmed up...
Check that first...if you run into a problem, feel free to send me a PM.