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.
Thanks MB