I've got a 97 suburban w/5.7L vortec w/120,000 miles. Recently it's
developed a misfire. OBD-II scan returns only one code indictating
misfire detected on #1 cylinder (P0301) No other generic or enhanced
pending/hard codes identified. I've replaced the cap,rotor, wires and
plugs (gapped @60). This misfire is present at all rpm ranges but
obviously most noticeable at idle or when first engaging transmission.
The odd thing is that randomly it will dissappear under accelleration
as if someone flipped a switch and will run clean for awhile. I erase
the code and all is fine during the vehicle operation in which the
misfire clears up, but usually the next morning problem resumes. Any
help or furher diagnosis steps is greatly appreciated.