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Q: fluctuating rpms and speed odometer

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I have a silverado hd 2500 with Hugh highway miles but the problem I'm having is when accelerating it seems to bogg down and rpms go way up and speed odometer bounces up and down then when I let off accelerater it goes to the speed I'm going I tried getting the computer read but the parts stores said it won't read what can cause this

My car has 200000 miles.
My car has an automatic transmission.

It sounds like the transmission is slipping and causing the RPM to go high and the speedometer to jump when the transmission is slipping. Have the computer tested for communication problems and the transmission for slippage. A technician from YourMechanic can help you pinpoint the issue so that you can diagnose both your acceleration and speedometer problem.

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