I recently got a 97 FX 2.0L, with lots of miles (221000km). It is still in great shape, but I can't get any high end power.

It idles fine, and runs smooth in the lower rpms, but the power drops off around 4000 rpm, and it won't rev past about 5000 rpm, even out of gear. There is no CEL on anymore. It doesn't flash when I drive either.
Has anyone had this type of problem before???
Any tips or things that I should look for?
I have access to an OBD2 scan tool that does live data too.

The story:
I bought it with the CEL on, knowing that it was a B1 O2 code. I replaced the front O2 sensor with a new one from a local auto parts shop, not a universal, but not from Hyundai either. I also replaced the air filter, fuel filter, and plugs. The previous owner said he did the timing belt, plug wires, alternator, and got a MAF from a wrecker.

I tried spraying some cleaner around the intake and hoses while the engine was running to try and find a vacuum leak, but the idle didn't change.

Any idea what would cause this?

Thanks!

 

Bad (clogged) catalytic converter or muffler could.

 

^^^ i second that. it happened to me.

 

^^ Plugged cat is a possibility., check throttle cable make sure its not loose,remove tps(2 screws)make sure it turns freely......

 

Spidey Shark, did you have similar symptoms when the CAT was plugged on yours?

What exactly is plugging it? Rust/carbon? Is there any way to clean them out (chemically or mechanically)? Can I somehow test to verify that the CAT or Muffler is plugged?

If the cat was plugged won't it throw a CEL, wouldn't the B2 O2 sensor readings be out to lunch? or no?

The throttle cable is fine, but I will check the TPS when I get a chance.

Thanks for the replies.

 

There is no way that I know of to clean them, only change them out.

May have to re-read codes, just in case your cel bulb burned out. They're free anyway.

 

Cracked exhaust manifold caused mine to not rev over 4k

 

i had almost the exact same problem. i had driven my car with a misfire too far to get to autozone and it melts the internals of the cat. when me and my buddy took it apart grey rocky looking stuff which was the cat internals fell out. i dont believe you can clean it out with chemicals, but maybe if you take it apart. i think an exhaust back pressure test would be able to tell you if thats your problem. and i didnt have a cel, the gas still comes through. if it didnt your car wouldnt run