I have a 96 Sunfire that cuts-out on the highway. We've done a tune-up, replaced all filters and pcv valve, replaced wires, and it still does it. In park, you can rev the motor up to 4000 rpms and she will cut out, rev back to 4000 rpm, cut out, etc. Fuel pressure is okay. Diagnostic says no problem. My mechanic is scratching his head.
Help me please.
Rick