Vehicle won't shift into 4th. High rpm at 60 and won't sh...

Q: Vehicle won't shift into 4th. High rpm at 60 and won't shift but get a pcv code

asked by on September 05, 2017

Car jerks when shifting into gears. High RPM at 60 and above and won't shift into gear but when using a scan tool it pulled up a lean code. What shall I do?

My car has 160000 miles.
My car has an automatic transmission.

Too much air flowing into the intake causes the engine to lean out, as a result of too much air in relation to the fuel and misfire. At an idle, the PCV valve restricts air flow, to reduce this problem. At high manifold vacuum (idle), a spring loaded valve is drawn up and partially restricts flow to the crankcase. The PCV system is relatively simple. An inlet hose connects to a filtered air source. This is used to supply clean air that is drawn through the engine. Most of the time this air is supplied through the engine air filter. On a few designs there is a separate inlet filter that cleans the incoming air for the PCV system only. This filtered air flows through the engine, picking up fumes and vapors. The air exits through another hose, connected to manifold vacuum. The flow of air draws fumes from the crankcase and burns them harmlessly in the engine. This also creates a slight vacuum, relieving any pressure that may build. Negative pressure helps to prevent oil leaks and oil consumption by the engine. The PCV valve also helps regulate the amount of air flow, which helps prevent oil being drawn out of the engine. When the PCV valve is not working correctly, this will cause an imbalance in air flow and vacuum causing the check engine light to come on. This may also cause problems with shifting due to the ECM attempting to identify shift points that are inconsistent with what it thinks they need to be as a result of the lean fuel condition. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your PCV valve.

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