Rep Power: 0

So, my 2001 civic ex has about 301,700 miles on there. I've had this car since for sometime now and bought the car with 91,000 miles. I used to get the car to 140-150 MPH. Now I'm having a hard time getting it past 100 MPH. The engine is leaking small drips of oil from the oil pump seal (which I replaced the oil pump and the seal on the new pump and still leaks). I have a check engine light that come and goes for the catalytic converter. But now the check engine light has stayed on. Also, I've noticed that the engine has pretty much no oil when I drive it about 1,500 miles. I used to change my oil every 3,000 miles but now I'm adding oil until I hit 3,000 miles and replace the oil filter when I hit 3,000 miles. So, I know my oil is going somewhere other than it should be and clogging up the catalytic converter. Now one person is telling me that it's the piston rings and another person is telling me that it's going around the valves somehow and that's why my catalytic converter is being clogged. Is there some who could help me with this issue?

I apologize for all these details. I feel like I'm writing all of this and explaining my problem poorly.

I'm hoping someone know how to fix this and explain why this is happening.

 
Rep Power: 244

So your catalytic converter needs replacing and your oil control rings are probably worn and or the valve seals. You can do a compression test to make sure (wet compression test I believe). Either tear the motor down and rebuild it or replace with a lower mileage one.

 
Rep Power: 119

Brand new, my 2003 couldn’t get past 125......

But yes, your engine has seized oil control rings and likely worn out valve stem seals.

You likely will start getting MIL codes for catalytic efficiency errors soon or already.

 
Rep Power: 0

Where would you drive it at 150mph? Are you in the US?

 
Rep Power: 224

WHAATTT?!?!? WHYYYYYY??

The theoretical top speed of this gen Civic is like 117 mph. I could see 120 mph, even 125 mph, but there's no way a seventh gen will go that fast.

 
Rep Power: 229

OP probably has Canadian model, doesn't know his track is in km. Lol.

 
Rep Power: 0

Hello, thanks again for the advice. I went to do a compression test and followed instructions from my Chilton's manual. My readings from my test were:

Cylinder 1- 205
Cylinder 2- 210
Cylinder 3- 200
Cylinder 4- 215

The manual states that the minimum psi is 128 and maximum variation between cylinders is 28 psi.

The manual also says that if compression is low to add a little bit of oil to the cylinder and test it again to see if psi increases. If it does, the piston rings are worn.

Since the lowest cylinder reading was cylinder 3 I added some oil and the new reading came out to 220 psi.

I am not sure if I was supposed to add oil to all 4 cylinders to see if psi would increase but I just figured to do just that cylinder since it had the lowest reading.

I would like to know your thoughts on this. Could it be possible that only cylinder 3's piston rings are the only ones bad? Or do I have to test each cylinder again?