Q: rough start, runs well, after it warms up

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Has codes of po174, po420 & po340. When truck first starts, seems to want to "kill", unless given extra gas. Once truck warms up, seems to run fine. Any idea, where to start looking for the problem?

Thank you,


My car has 169000 miles.
My car has an automatic transmission.

Hi there. The OBD-II Code P0174 indicates that there is a lean condition detected by the Engine Control Module (ECM). A lean condition will be created if there is too much air, and not enough fuel, in the air fuel ratio (AFR). This is why your engine want’s to stall unless it’s fed with more fuel. Some of the common components that cause this problem include a dirty mass air flow sensor, a tear in the MAF vacuum lines, or a faulty O2 sensor. If you would like to have a professional mechanic inspect this problem and complete a engine runs rough inspection; feel free to contact our team.

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