Originally Posted by wjcollier07
hmm...i would say...maybe your octane level is too low...i dunno why that immidiately comes to mind...
or basically plugs, wires, vacuum, coils? not sure other than that
Wow, this one went WAY out in left field.
Lower octane fuel will NOT cause misfires. It retards timing evenly.
Vacuum leaks are most apparent at idle, not cruising.
This is an ignition problem. Plugs and wires as stated (stay away from Bosch, and stay away from ALL platinum plugs. Copper or Irridium only). Stay away from Bosch or Taylor wires. Both have very bad reputations here. OEM wires or Belden Premiums from NAPA are best bets.
At the same time, follow the coil pack troubleshooting in Techinfo (link at the top of the page, or search the Techinfo for 'coil'). You may also find rust on the coil secondary terminals. This is common on the Series 2 motors. If you do, clean them well with a wire brush and some scotch-brite (in the body/paint section of the parts store), and reassemble with dielectric grease. Also put some of the grease inside both end boots of each wire to keep water and such out, and make your next plug or wire change much easier.