Buick Repair Questions? Ask a Mechanic for Answers ASAP
Hello and thank you for your question!My name is ***** ***** I will be assisting you with your question today.
Lack of engine speed and vehicle speed will cause poor shift quality.
With the issue you are having it indicates, as you suggested a possible ECM issue or a communication issue between the instrument cluster and the ECM as well as the body control module.
Locating the reason for the failed instrument cluster should resolve the problems you are experiencing with the shifting as well.
Please let me know what more I can do to assist you today. Also, please remember to rate my answer, Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, or have a subscription a rating is still required.Thank you so much!
Do you need more help with this?