I have noticed over the past 3 weeks or so that the cranking time required to start the truck is gradually increasing... Does not seem to matter if it's cold or warm (either ambient or engine temp)... It's not cranking slow, just cranking longer. Any ideas what to start looking for? Runs just fine once it's going. For reference:

* Newer plugs/wires/cap/rotor (less than a year and maybe 5k miles on them)
* Good fuel pressure
* Brand new battery (withing 30 days)
* MSD 6AL box and MSD coil
* Timing set to 10* when tune parts were replaced last spring

 

Any other changes? Idle rpms, gas mileage, oil or coolant consumption? What about ambient humidity?

 

Haven't noticed anything abnormal in any of the above...

 

Pop the distributor cap and take a look. I put a cheap gray one on when I did my tune-up and about a year later, I poped the cap and found all the connections had white crud on them. My cranking time was getting longer as well. When I scraped the crud off, the engine fired faster then I could let go of the key. Hope this helps.

 

I'll definetly check that out, thanks for the idea!! FWIW, the cap/rotor I used were MSD parts (as were the plug wires) straight from Summit last May...

 

I know this may sound dumb but your battery may be on the way out. Have you checked it? My car battery recently died and for about a month it took longer to start it at random times. You can try another battery if you want. Also I'd look and see if it has a dried cell in it.

 

Mine just started this yesterday but I suspect my rear fuel pump is going out. It doesn't seem to do it on the front tank.