Not accelerating past forty mph

1997 PONTIAC SUNFIRE
200,000 MILES • 2.2L • 4 CYL • 2WD • AUTOMATIC
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RAYMOND C. ALVAREZ-VELEZ
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My car will turn on perfectly, run, but when I try to accelerate past forty mph, the revolutions drop which reduce my speed, so I cannot get past forty mph. Also, when i am parked and the car is on i can smell gas. Check engine is on.

I replaced the following:
Spark plugs.
Spark plug wire set.
Mass airflow sensor.
Throttle position sensor.

I added the following: transmission fluid.

I was told by AutoZone it could be the throttle control solenoid, idle air control valve, or that it needs a cleansing of the throttle body.

By the way, when i try to use a computer to read what is going on, I cannot get anything but that has not stopped me from driving past seventy mph on the highway before. What else could it be?
Mar 21, 2018 at 3:53 PM
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HARRY P
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Sounds like a clogged catalytic converter to me. Or possibly low fuel pressure. Take out the first oxygen sensor when the engine is cold. Then go for a drive and see if it does better. If so, then you have a clogged catalytic converter. What is happening is it is not allowing the engine to breathe and too much back pressure is building up, restricting the engine, and causing it to shut off. Just be careful of when you go for that drive. It will be "wake the neighborhood" loud.

Let us know what happens and we will go from there.
Mar 21, 2018 at 7:03 PM
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RAYMOND C. ALVAREZ-VELEZ
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HEYMAN1104, I tried doing that. It seems like it had a worse performance. I just got a new reader and it shows that the O2 sensor is bad. I took a look at the O2 sensor and it looked pretty dirty and worn, so i am going to buy a new one and try it out. Afterwards I will look at the knock sensor. What is odd is that even though I changed the MAF sensor the reader is telling me that there is a MAP sensor error, but i do not think this car even has a MAP sensor since cars usually have one or the other. Besides that if nothing works I think it might be the wires are damaged somewhere along the way. What do you think?
Mar 21, 2018 at 8:07 PM
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HARRY P
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It does indeed have a MAP sensor. I am attaching all of the pertinent information that GM has provided on it in the images below. Please check it out and go from there.
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Mar 21, 2018 at 8:27 PM