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
Jul 3, 2019 at 7:16 PM
