Every time I shift my truck from park or reverse into drive the engine rpms severely drop and sometimes stalls. It idles in park at ~750-800rpms and drops to ~400rpms in drive before it bounces back to ~700rpm. However if I start my car in neutral and shift into drive everything is fine. Also if i rev up the engine while shifting into drive the engine still drops significantly in rpms, but does not stall. Once in drive it operates great. Shifting into park, reverse and neutral are normal. I've already replaced the neutral safety switch and idle air control valve with no success. Any ideas?
My car has 176000 miles.
My car has an automatic transmission.
Hi there. The vehicle running great, once past the initial stall, leads me away from a fuel delivery concern. The stalling issue may be, the minimum airflow rate is not properly set. This could be the result of a dirty or worn throttle body. Cleaning and/or making an adjustment to the throttle body may correct the problem. Engine running at idle, plug the IAC passage, and the RPM (revolutions per minute) should be at or near 400 rpm. A vacuum leak present could also cause the engine idle to be improperly controlled and needs to be identified before any adjustments are made. I recommend having your vehicle's stalling issue be diagnosed and repaired by a certified technician, such as one from YourMechanic.
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