92 Park Ave with a performance problem

My Park Ave has a problem in the 3000 to 4000 RPM range. Appears to be running very rich in this range as you can see black smoke pour out the pipe and it has no power. Since I've owned it, it never has seemed like it had the power it should.

It died on me about a month ago. Got it to the shop and they found a bad fuel pump. After replacing that it still didn't run right. They next found the magnet on the timing gear to be nearly missing which shouldn't have allowed it to run at all. Still the problem remained. They then started replacing coils, plugs, wires, turbo boost solenoid, etc. Cleaned the injectors. Still nothing. They then took it to a GM dealership to get their opinion. They couldn't figure it out, but suspected a problem in the SC. I bought a reman SC from Performance Solutions and it helped it some. My mechanic has finally given up.

I picked the car up last night and it is drivable, but would like to get the problem resolved. I'm open for any suggestions. I'm leaning torward buying new injectors or maybe replacing the PROM in the ECM.

Barry

Hi Barry.
Maybe you have trouble with the Intake Air Temperature Sensor (IAT) or the Mass Air Flow Sensor (MAF).

Description:
IAT: The ECM supplies a 5 volt signal to the IAT sensor through a resistor in the ECM and monitors the voltage. The voltage will be high when the manifold air is cold and low when the air is hot. By monitoring the voltage, the ECM calculates the air temperature and uses this data to help determine the fuel delivery and spark advance. A failure in the IAT curcuit should set either a Code 23 or Code 25. Once the trouble code is set, the ECM will use an artificial default value for the IAT and some vehicle performance will return.

MAF: The MAF sensor measures the amount of air which pases through it. The ECM uses this information to determine the operating condition of the engine, to control fuel delivery.

Mike

After six months, my PA is finally fixed. It runs like a new car now. About a month ago the harmonic balancer came apart on it. Replaced it and the performance was slightly better, but nothing to write home about. Last week the battery completely died. Replaced it and after the computer reset itself all my engine problems were gone and the performance is where it should be.

I can only guess that the old harmonic balancer was wobbling causing a hit/miss situation on the crank sensor. Resetting the computer put everything in order.

Barry

I would check your TPS sensor.. make sure that is in order and also 02 sensor.