Engine won't stay running, stalls while driving?

Have a helper crank it, while you check for spark at the spark plugs, when problem is ongoing. If you have spark everywhere, use a gage and check fuel pressure. Some of the national brand autostores used to loan out a fuel pressure gage.

To check for spark, where applicable, take a spark plug wire loose, use a spark tester in bott. Ground/touch metal part of tester to metal part of engine. Engine cranking, watch for spark.

First thing you should do is scan for faults. There should be faults stored if the vehicle is stalling. If not I would suspect a possible vacuum leak or idle air control valve since the idle is changing from 500-1000rpm

Any of the items you listed could cause the aforementioned problem. However, you should still be able to scan the computer to determine if there is a trouble code that would point you in the right direction. Have you done that? Also, I would recommend checking for engine vacuum leaks.

Please keep in mind, considering the amount of work that has been done to the engine leaves many possible things to consider. However, considering the IAC does maintain engine idle speed because the throttle plate fully closes when you let off the gas, that would be the first thing I would suspect. Also, the idea of a vacuum leak could also be an issue.

Hello! Thanks stopping in!

For better service here can I ask you start a new question. Just click on this link: https://www.2carpros.com/questions/new
Then tell us what vehicle you have and then describe your problem.

It’s just that this is a old post this will get you better service!

Jon