Cat cut off and straight piped, no oxygen sensor reinstalled, engine will not stay running unless I pump the gas pedal?

Hi,

The oxygen sensor is used by the powertrain control module to determine the needed air/fuel mixture for the engine. Certainly, they can cause this type of problem.

However, here is what we need to try. See if there are any diagnostic trouble codes stored that may help point us in the right direction. This has an OBD1 system and doesn't require a scanner to retrieve codes. All you need is a short jumper wire or even a paper clip. Follow the directions in this link and let me know what you find:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Also, make sure no vacuum hoses are damaged or disconnected.

Let me know what you find.

Take care,

Joe