2000 Honda Civic lacking power

I have a 2000 Honda Civic Ex automatic 225k miles on it. Recently replaced spark plug and spark plug wires. Just had an oil change and an inspection done; they found an oil leak in the oil pan (oil pan cover gasket needs replaced). I have a severe lack in power, meaning it doesn’t have the get-up-n-go it should. Doesn’t shift until it hits 3.5 rpms, idles pretty loud, and noticed earlier today that there is a rattling that seems to be coming from front drivers side(could of been the road, adding it in for good measure) but that didn’t happen till i hit 65. The coolant tank has a black grime in it, and from what i understand that’s from deteriorating hoses(?). My question is this: What could be causing this loss of power? Anyone have similar issues and what steps did you take to fix it? any feedback would be appreciated

Lack of power is usually the result of low compression, obstruction in the intake air path, obstruction in the exhaust path, or not enough fuel flow.

My guess this is a clogged cat. But I wouldn’t start there probably. Well, no harm to check to see if a neighbor kid put a potato in the tail pipe. I think it is pretty easy to test the compression on a 4 banger Civic, so that’s probably where I’d start. Next I’d make the sure air filter is clean as a whistle and no rats/mice/birds nests in the air intake tube. Next would be a fuel pressure test. If all that checks out ok, ask your shop to remove the pre-cat O2 sensor temporarily and see if that helps. Hint: Wear ear plugs. If it does, it’s an indication of a clogged cat.

“The coolant tank has a black grime in it, and from what i understand that’s from deteriorating hoses”

Who told you that?
The most likely cause of “black grime” in the coolant tank is from a breached head gasket that is allowing motor oil to seep into the cooling system–and that’s not a good thing.

I would recommend that you have your mechanic do a compression test, and also use his “sniffer” to determine if there are byproducts of combustion in the coolant. If he finds byproducts of combustion in the coolant, that would confirm that there is a breached head gasket. Additionally, the head gasket breach could reduce engine compression sufficiently to reduce engine power.

If the transmission doesn’t shift until the engine hits 3,500 RPMs, that could indicate a slipping transmission, and–once again–that’s not a good thing.

If you have a breached head gasket and a slipping transmission, I believe that it is time to retire this 14 year old car. Just one of those problems might be enough to retire it, in light of the car’s low book value vs the cost of repair, but if you have both of these problems, I believe that it is just not economically practical to repair it.

I’m with VDC on this one. He’s given you good advice, as he usually does for people.

I could think of a number of things that could cause this but without additional info it’s difficult to even get in the ballpark with an answer.
Slipping transmission, worn out engine, sluggish engine due to a timing belt installation error if applicable, clogged catalytic converter, etc, etc, etc.

How’s the transmission fluid level? Maybe the gunk in the coolant bottle is transmission fluid which is leaking into the cooling system via a faulty fluid cooler in the radiator. By the same token, coolant can get into the trans fluid and end the life of an automatic very quickly.

I’m also in agreement that if the transmission and/or engine are on their way out it may be time to say goodbye to the car given the age and mileage.