Like Jer said, you can never rule out the wiring harness or the M16 throttle actuator, unless you cut the harnesses open and verify that the wire insulation is not cracked/brittle/powder; if they are, start budgeting, because any good mechanic is going to require you to replace at least the wiring harness before he starts diagnosing the problem. In fact, remove the airflow intake tube off the top of the engine and remove the spark plug cover in the middle of the valve cover. slice the ignition coil control wires open (NOT the actual spark plug wires mind you) and verify that the control wires have not one single crack in the wire insulation; if they do, save yourself some diagnosis headaches and replace the harness. Had one come in 2 weeks ago with the exact problem, and you should have seen the control wires!!!

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Don't ask me, I'm a shop-owner by default