Hesitates and stumbles

More than likely, it is not the crank sensor. Basically, this sensor tells the ECM the position of the crankshaft so that it can fire the plugs and injectors at the right time.

If there is no crank sensor signal, then the engine would not run at all. So, if you can keep it running above 3000 RPM then the crank sensor is fine.

This most likely is one of two things. Either a vacuum leak which is most likely. Or a fuel pressure issue.

So, let's start with a vacuum leak. Here are a couple guides that will help with this.

https://youtu.be/4ktw1X4W_-k

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Basically, if there is a leak then there is air coming into the engine that is not being measured and the PCM does not know to add more fuel for that air, and it throws off the air fuel mixture which does not allow it to run properly.

Plus, here is a guide that will help with fuel pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run through this info and let us know what you find.

Hi,

It could be several things. First, an engine vacuum leak can cause issues. Also, fuel pressure or the need for a tune-up can cause it.

Let's start simple. If you haven't already, check to see if there is an engine vacuum leak. Here is a link showing how that is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me get a little more info from you. At idle, do you notice a misfire or rough idle? Is there any smoke from the exhaust or odd odors from the exhaust?

Here is the procedure I have for retrieving codes. Is this what you performed?

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

Is this the original engine having 240,000 miles on it? If so, it could be a compression-related issue.

Let me know as much as you can. Oftentimes, you can have a miss at all speeds, but they become less noticeable when the RPMs are higher.

I will watch for your reply.

Take care,

Joe