How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask rpmdiag Your Own Question
rpmdiag, Tech and Instructor
Category: Car
Satisfied Customers: 7740
Experience:  Since 1975
Type Your Car Question Here...
rpmdiag is online now
A new question is answered every 9 seconds

94 Olds: operating temp..freeway..The speedometer will back

Resolved Question:

My 94 Olds dies on me when reaches operating temp. This can be driving in my neighborhood or even on the freeway. The speedometer will spike then the car dies, I can start the car back up again right away, most of the time I have to pull over to do that. I've replaced all vacuum hose's, The ignition module, spark plugs, retighten all cables, even put on new gas cap. Nothing helps. Please help me, Jim
Submitted: 7 years ago.
Category: Car
Expert:  rpmdiag replied 7 years ago.



Test the CRANK sensor with a scope, this can be tough, but it can be done by watching the signal while driving the car when this happens. Then take a snap shot of the waveform. It's not hard to do either. Here's a pic of how it should look if it's good.


Thanks for your question,





Customer: replied 7 years ago.
so what does this sensor senses and if this is my problem why does my car dies or shuts off
Expert:  rpmdiag replied 7 years ago.

Crank shaft position signal for #1 cylinder to the computer. When the sensor wears out, it can no longer withstand the heat that it's subjected to and does exactly what your symptom is.


Thanks again,



Customer: replied 7 years ago.
how exspensive of a repair is it to have that replaced.
Expert:  rpmdiag replied 7 years ago.

Under $100.00 should do it for part and labor


Thanks again for your SUPPORT,



rpmdiag and 5 other Car Specialists are ready to help you