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First put a fuel filter on it. There is no such thing as bad gas. The octane rating goes down as time passes, but the gas will still run the car. The alcohol in the gas may have damaged the fuel pump or rubber hose in the tank.
Does the car act differently after running for over 5 minutes (closed loop operation)?
If so, check the ground a the passenger's side of the thermostat housing. Remove the nut, and the lugs, and remove the stud (when the engine is cold). Clean the stud threads, and the threads in the hole. GM thought it was a good idea to put two dissimilar metals together near water.
Then if it still does not run properly, you may have an errant fuel pump or the soft line inside of the tank may be cracked. If the line in the tank is cracked, it will pump the fuel into the tank instead of the TBI. Pressure will be low, and the flow pattern may suffer because of it. Adding "fixes" to the gas tends to cause degradation of the hose. If you pull the tank, put a new AC Delco, or Delphi pump in. Do not use any other brand. It is difficult to get the fuel pressure checked, because the wonderful engineers at GM deleted the Schrader valve on the pressure line for the B bodies.
It could also be your plug wires, or cap and rotor, depending on how old they are. I think it is something else, but there is the possibility of the wires being bad.
If it is acting up more after 5 minutes, it could also be the O2 sensor.
Since it idles OK, you know you do not have a vacuum leak.
Check your EGR valve, and the solenoid that controls it.
Another easy parts swap is the MAP sensor on the firewall. They are known to cause similar issues, but are usually not a problem. Make sure the hose between it and the back of the TBI is connected.
Do not replace the TBI, it is not the issue.
Try turning the ignition switch on with out starting the engine, and listen to the fuel pump whir. Try recycling the switch after a few seconds, and listen to it again. If it runs about the same every time, you may have a fuel pressure issue. It should run less on the second and successive try.
Did you check for any codes? If you cross the A and B pins on the ADL connector under the dash to the right of the steering column, the service engine light will blink for the two digit codes. You must put the key in the run position, and have the engine off. It will flash a number of times and then once and twice for 12. 12 lets you know the computer is operating. It will show 12 three times, then any other codes in the same manner. If it has codes, let us know.
If there are no codes, you can probably assume it is fuel or spark, because they do not throw codes.
Does the car act differently after running for over 5 minutes (closed loop operation)?
If so, check the ground a the passenger's side of the thermostat housing. Remove the nut, and the lugs, and remove the stud (when the engine is cold). Clean the stud threads, and the threads in the hole. GM thought it was a good idea to put two dissimilar metals together near water.
Then if it still does not run properly, you may have an errant fuel pump or the soft line inside of the tank may be cracked. If the line in the tank is cracked, it will pump the fuel into the tank instead of the TBI. Pressure will be low, and the flow pattern may suffer because of it. Adding "fixes" to the gas tends to cause degradation of the hose. If you pull the tank, put a new AC Delco, or Delphi pump in. Do not use any other brand. It is difficult to get the fuel pressure checked, because the wonderful engineers at GM deleted the Schrader valve on the pressure line for the B bodies.
It could also be your plug wires, or cap and rotor, depending on how old they are. I think it is something else, but there is the possibility of the wires being bad.
If it is acting up more after 5 minutes, it could also be the O2 sensor.
Since it idles OK, you know you do not have a vacuum leak.
Check your EGR valve, and the solenoid that controls it.
Another easy parts swap is the MAP sensor on the firewall. They are known to cause similar issues, but are usually not a problem. Make sure the hose between it and the back of the TBI is connected.
Do not replace the TBI, it is not the issue.
Try turning the ignition switch on with out starting the engine, and listen to the fuel pump whir. Try recycling the switch after a few seconds, and listen to it again. If it runs about the same every time, you may have a fuel pressure issue. It should run less on the second and successive try.
Did you check for any codes? If you cross the A and B pins on the ADL connector under the dash to the right of the steering column, the service engine light will blink for the two digit codes. You must put the key in the run position, and have the engine off. It will flash a number of times and then once and twice for 12. 12 lets you know the computer is operating. It will show 12 three times, then any other codes in the same manner. If it has codes, let us know.
If there are no codes, you can probably assume it is fuel or spark, because they do not throw codes.
