Myfi Jetpac working poorly

Try a Netgear MIMO antenna:
https://learntorv.com/netgear-hotspot-antenna/

I think they said They had to change the SIM card because I had had a temporary account.
Last night when t jet showed .5 download speed I did a speed test using my IPhone as a hotspot. 22.8!
So the Jetpac seems to be the issue.
We are from Kanada so if I was to just use my phone as a hotspot our cost would be much higher.
According to the pac and phone it would appear we have very good signal strength.
But I will down load the app. Thanks for the tip.
At the moment phone hotspot 70+ download speed. Jet .50

A jetpack , like any other cellular device, requires a good signal. Have you verified you are getting a good signal to the unit? An app like Opensignal will help determine what towers are near you and what sort of signal strength you are getting. Throttling wouldn't be intermittent. Once you reach a threshold it will slow down until the next cycle. I know on our last jetpack it was pretty finicky about where I placed it in the RV. I bought a small antenna for it and that really helped. Also, if you are happy with your phone as a hotspot, what do you need a jetpack for and why did you change the sim card?

Years ago, I had a hotspot that worked great, until it didn't. No idea what happened and it was replaced by the carrier, but it just stopped working properly. Very weird.

Sounds like throttling based on whatever plan you are on.