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Car shifts late and hard

2000 cavalier z24 2.4 170k autom

At first I thought this was a transmission fluid problem but had it checked and it’s full. This may be a combo of 2 issues. At first it shifted so hard I couldn’t really drive the car. AutoZone computer said the tp sensor needed replaced. I got the tp sensor and the issue did change for the better in that I can drive the car now but there is still a problem.

Its an automatic 2000 cavalier z24 2.4. shifts hard into drive and through the gears, although a bit softer into 3rd and 4th. The weird thing is, and this is how I manage driving it with less issue, is that if I slightly let off the gas real quick and push again when I think it should shift normally, it does. Every time. If I don’t let off the gas and push again slightly it will shift late and hard which I imagine isn’t good for the trans to deal with.

Any advice would be appreciated. Not sure if it might be something like a speed sensor or what. I’m an auto repair noob.

Maybe you just need a transmission tune-up or the automatic clutch is worn.

Question - how far have you driven it since you changed the TPS?

Also I would have the technician verify that the TPS is calibrated correctly i.e. that the reading at idle and Wide Open Throttle match the specifications. Also look at the supplied voltage to the sensor. IIRC the should be 5 volt DC. If this is out of tolerance, the TPS signel will be out of specs.

Agree with @researcher Also disconnect the battery and let the computer “re-learn”. May fix the problem.

Speedo works fine?

You’re probably going to have to go to a transmission specialist to get to the bottom of this. It might be something simple to fix, like a faulty solenoid. But one idea short of taking it to a specialist is to inspect for broken transmission or engine mounts.

Having the computer “relearn” is what I was driving at in my previous post. The TPS is one of the sensors that controls shift points.

I once replaced an IAC in an '89 Grand Prix and had to drive it about 15 miles before the idle speed would settle down.