i have a 2000 nissan quest. it has a intermittant rough idle only after sitting at a light for a min. It was idle fine at light then just start idleing really rought, i have to rev it up and then drive. The van has a new iac valve, throttle position sensor and egr valve. It had the issue before these parts were changed as well. There is a check engine light p0135. 02 sensor light, both sensors are brand new. light is still on. Any ideas?

Try running some fuel system cleaner containing polyether amines, which is a chemical proven to clean deposits without leaving behind its own residue. Products which are known to contain PEA are Chevron Techron, Gumout Regane, and Redline SI-1.

Try cleaning the throttle body if you haven't yet.

For the P0135 code, follow the diagnostic procedure on page EC-225 of the factory service manual.

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