Question Replaced timing belt/water pump...idled rough...drove around for a few minutes...still ran rough. Replaced cap and rotor and plug wires. Shows p0700 & p705 codes. I assume i need to replace the speed sensor? Am i correct? Any input is appreciated!!
Answer Hi Brent,
I assume that this is the 3.0L engine. The codes you listed pertain to the automatic transmission rather than the engine. The relevant code is the 0705 which points toward a problem relating to the transmission range sensor switch circuit. But that would have nothing to do with rough idle of the engine or running rough.
Without an engine related fault code one has to consider the possibility that the timing marks are out of alignment in light of the job done to replace the timing belt. Did you verify those?
The only other item that often causes rough idle but without a code is the exhaust gas recirculation valve. The valve can get gummy around the operation of the valve stem and then it tends to stick slightly ajar which leans out the idle and low rpm mixture. So spray some WD-40 on the shaft of the valve where it enters the valve body, then mover the valve stem by means of a screwdriver tip inserted in the stem of the valve to verify that it is closing to a dead-stop by means of the internal spring action.
Keep watching for other fault codes in the under 700 series.
Please read the PS (below) and respond to it.
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