Welcome to 2CarPros.
Honestly, it sounds like either you have too much fuel pressure or a plugged catalytic converter. We need to start by checking for diagnostic trouble codes. The vehicle has an OBD 1 system and can be checked without a scanner. All you will need is a short jumper wire or even a paper clip. Follow the directions in this link:
https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method
Next, we need to check fuel pressure. Here is a link that shows how it is done:
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Here are the specifications specific to your vehicle:
FUEL PRESSURE:
Ignition "ON" Engine "OFF" .................... 40.5 to 47.0 psi
With Regulator Vacuum Applied [1] ..... 3.0 to 10.0 psi Less than Ignition "ON" Engine "OFF"
REMARKS:
[1] May be checked with either of the following methods.
With Pressure Regulator Vacuum Line Attached at normal idle speed.
Ignition "ON" Engine "OFF" with 10 Inches Of Vacuum Applied To The Pressure Regulator.
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If the pressure is good, we need to confirm the catalytic converter isn't partially plugged. Here are a few links to explain a faulty converter's symptoms, how to check one and in general directions for replacement.
https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
https://www.2carpros.com/articles/how-to-test-a-catalytic-converter
https://www.2carpros.com/articles/catalytic-converter-replacement
Do these tests and let me know the results.
Take care,
Joe
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Wednesday, July 3rd, 2019 AT 7:16 PM