Hello,
It sounds like you have a one of two problems, the first will be a plugged catalytic converter which will cause the vacuum of the engine to be low and make the transmission shift late and not go into overdrive.
Here is a test that will confirm the problem,
https://www.2carpros.com/articles/how-to-test-a-catalytic-converter
The other would be a MAF sensor that is off. I would try cleaning the sensor first. Here is a guide for that as well.
https://www.2carpros.com/articles/mass-air-flow-service
This will cause the readings to the computer to be off and cause the same problem.
Please let us know what happens.
Cheers, Ken
Monday, August 14th, 2017 AT 9:13 AM