Goes to limp mode tac.quit
You are really going to have to give us more to work with here…
What are the codes??
And what exactly is happening in much more detail please…
The tach gets its signal from the crankshaft position sensor. And if the computer can’t get a tach signal, it’ll go into a limp mode.
When these sensors go bad, it doesn’t always turn on the Check Engine light.
Tester