Start with the CEL. The amount of info you posted is not enough to do any real diagnostics. Unfortunately there can be any number of things causing this ranging from fuel to exhaust to internal engine. You not only need to be able to read and understand the scan data but have knowledge of how the internal workings of the engine. If not, your just guessing.
"IF" you actually have a low power complaint.
1. it may not be getting enough fuel. Pump, filter, O2 not giving the computer correct info, other sensor not giving correct info.
2. Exhaust. Cat came apart, muffler plugged
3. Not enough air. Air filter, something weird with the throttle.
4. Engine issue. Camshaft, timing belt/chain.
5. Another sensor lying to the computer. Knock sensor can cause the engine to reduce timing. The problem doesn't necessarily have to be the knock sensor but another sensor giving false readings.
6. The symptom is actually something else but it seems like low power to you. Now you have another list to sort through.
I'm not trying to sound mean or troll you. This is what I have done for a living for several decades. Anyone who tells you what's wrong without actually driving and diagnosing the vehicle is guessing and doesn't actually do this for a living.
If you want to learn, get something that reads data, a good volt meter and the factory shop manual. Pull the code, follow the chart and compare the data. Test the parts with the volt meter. Unfortunately a good number of "mechanics" don't actually know how to do this or are too lazy to do it. They just throw parts at it and when its done tell you "it needed all this". The frustrating part of working this industry is being grouped in with those guys and the "internet mechanics".
Speaking as a professional, I will never use any electronic parts that are not OE. I could horrify you for hours with tales of how this or that part caused an issue it shouldn't have been capable of or having the part fail quickly, which make you second guess your diagnostic.
EDIT: Just realized the vehicle is a 93...Scan data probably wont happen. The nice thing is it actually got easier, bad thing is, everything is now tested with a volt meter.
@smritte
I wanted to respond to your paragraph of information, since you took the time to respond, which I appreciate very much.
I've owned my 93 TLC for about 2.5 years and have put quite a bit money into it for maintenance items that were bound to go. Doing this has helped me learn allot, giving me passion to do it myself, not withstanding things that I am not able to do on my own.
I am an engineer by trade but was an apprentice mechanic right out of HS, having worked on cars from the age of 11. I took a different path a few years later, going into my now professional life.
My 93' TLC and items replaced so far:
* Replaced ALL coolant hoses. ALL of them, including the PHH
* Both 02 Sensors and nuts
* EGR Valve, not vacuum solenoid, but eventually will soon
* Rear main seal
* Heater valve and all hoses
The previous gentleman I purchased my TLC from, owns quite a few TLC's and took over the business owned by an older gentleman named Bud, whom lived up in Clearlake, CA. I guess he's well known. I also know Ronnie Diaz, who lives near me and can also pick his brain if needed but he's quite busy.
I love that we have a community of people here at OB, where we can get some help in a pinch. No one knows everything, but blogging searchable information for future use is a great way for everyone to learn and I'm happy to be part of that.
Thanks again to all for the replies!
@Autism Family Travels @MOAK @Desert Runner