Idle Issues (1990 Buick Electra Park Avenue 3.8L 3800 Series 1)

I assume this does not have a maf? A quick test Try disconnecting your upstream oxygen sensor and see if straightens out

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how hard is it to check fuelpressureon this car? see what your losing when the stall happens....

Ok so with upstream oxygen sensor disconnected (thats the 1 in the manifold) it still don't run right correct?you said this had a sensor before the throttle body?

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Ok you don't have a way to read live data on obd1 do you?

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As you do not have neither data nor the required tools for some basic testing you´ll need a different approach:

How do your plugs look like? Any clues there, signs of lean mixture or engine running hot?. If you feather the accelerator pedal it won't stall?

I think your going to need to test them hot and the resistance will change with temp. However I would first check for spark when it is warmed up and running rough use a pair of insulated pliers and remove 1 plug wire from the coil pack at a time and note if engine idles worse or no change and make sure there is a spark arcing across coil pack when that wire is off(do not remove from the wire from plug you will get a jolt of a lifetime, dont ask me how I know) you'll either find which cylinder is dead or you'll find 1 coil pack isn't working

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