I have a GMC K1500 with the 5.7 vortec engine, 203,000 miles. It is getting hard to start, only started happening in the last 2-3000 miles. Fuel pump was replaced 25,000 ago, cap/rotor/wires replaced 30,000 ago, plugs replaced about 5000 ago.

About a week ago I got a PO300 random multiple missfire code going down the highway with the cruise on about 70mph. I scanned the code then cleared it, the code has not returned. It seems to idle and run fine once it is started but I am having to crank it longer and longer to get it started. I have been reading about the fuel pressure regulator issues but mine doesn't seem to have any other issues besides the hard starting. Could it still be the fuel pressure regulator? Thanks for any info you may have.

 

Having observed the hard start problem a little more it seems to be only when hot, after having been driven for a while. The hard start condition is not present when it is totally cold. Any ideas?