Transmission will not downshift for power

Hello,

It sounds like you have an input shaft speed sensor that is going out but to be sure lets run the codes to see what codes up. Here is a guide to help us get started:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here are the transmission wiring and speed sensor location.

Check out the diagrams (below).

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

The only code I get is P0443 about the Purge Control Valve- checked again yesterday. I heard it might go away by resetting the computer and so disconnected the battery for 1+ hour but the symptom remains. I replaced the Purge Control Valve several weeks ago- probably need to look at the electrical connection since it is still coding.

Hi Ken, thanks for responding.

Do me a favor with the engine running disconnect the vacuum line to the valve to see if there is engine vacuum present.

Yes there is vacuum. The wires look ok, the retaining clip snapped off the head but it seats well and does not slip out unless pulled.

Can you connected power and ground to the solenoid to see if it works? You should hear a click and then be able to blown through it.

There is a click, the solenoid operates connected to a 9v battery. Its old but the vacuum lines look ok.

I sounds like you may have a PCM going bad not shifting and the EVAP error. If you clear the codes and then turn the key on without starting the car does the code come right back?

The code remained clear for more than a day, but came back while attempting a minor acceleration at 60+ when the gear selection stuttered.In this situation I can press the pedal to the floor and the car will kick down and accelerate rapidly. The same3 thing happened near 30-35 mph on an onramp, looking to sort position, a little more pressure on the pedal resulted in stuttering acceleration until pressure was let up. Service engine light flashes in these instances- about 30 seconds then remains lit steady.

I had a thought, it could be you have a plugged catalytic converter which can cause the low power and shifting issues, Can you run this test and report back?

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please run down this guide

Cheers, Ken

Holy Moley I found it! My son talked me into replacing the Throttle Position Sensor which had no effect, so I took it to a shop. Hooked up to diagnostic equipment, with the brake depressed and throttle applied (loaded) the #3 cylinder was misfiring consistently, right off the screen. But no code would come. Replaced the #3 coil and all is good! No clue why it wouldn't code properly. Appreciate your effort and time, thanks and take care!

Nice work, we are here to help, please use 2CarPros anytime.

Cheers, Ken