cennouu

I have a 93 Civic Lx Sedan equipped with a D15B7. I noticed that i am losing power and that my fuel efficiency is bad. I cant even drive shifting at 3k RPMs anymore, i used to be able to but now i have to shift at 4k just to drive same speed as everyone else, this is what i think is the cuplrit to why i have bad MPG. I drive till almost empty and fill up 10 gallons of 87 fuel, i get close to 200 miles per 10 gallons (20 MPG). Mileage is 166k, original engine, everything is stock except for an intake on a stock rubber intake pipe. What is going on and is there any parts i should consider replacing? What about my MPG, what could be done to get my 30MPG back?

Also i have driven it to 5k and 6k very often, and since it has been handed to me it was never abused like that.

Kista20

sounds like the cat could be clogged up, any cel's? It wouldn't hurt to do a full tune up with plugs, wires, cap, rotor, pcv valve, air filter and fuel filter as well.

fv8s

You should be getting 30+MPG's with that motor/ chassis. Since the drivetrain is somewhat old I would start with plugs, wires, cap and rotor like Kista stated.

Kista20

the principles are the same but I had a toyota once and the cat was clogged and going to work I had to go up this hill that I always did it in 3rd but had to downshift into 2nd gear.

honda.lioness

Ditto all--cat converter is quite possibly the problem, but first do a full tuneup as listed above. Consider also a new, Denso oxygen sensor. Should run about $40 on Amazon or Ebay. Denso is the manufacturer for the OEM part.

Use only OEM recommended plugs, and OEM wires, cap, rotor and PCV valve. These OEM parts pay for themselves.

cennouu

Ok so ill do a tune up, replace oxygen sensor, and maybe put a new cat. I had no check engine lights. I was wondering if i should seafoam my engine, or do anything to increase power without buying new parts because the car was bought for 1 grand.