need help. using too much fuel. and other issues

[soufigured]

Hello, I'm in need of some help. I have a 93 civic si (d16z6) and I'm having some trouble diagnosing my problem(s). So to start off I've had my civic for just about a year and over the last couple months I've noticed it using a lot more fuel, very rich exauhst, lackluster performance. Since the day I got it the rpm goes up to around 2000 at start up and then drops down to normal once its warmed up witch may just be because its a 22 year old motor with over 420000 km (about 260000 miles) or it could be a clue to my problem. I've since replaced my air filter, fuel filter, manifold o2 sensor, cap, rotor, coil, plugs, and wires. Now at start up it still idles high till its warm but for the first couple seconds there is a fresh gas smell, it still uses too much fuel and has no power most of the time but sometimes it seems to run just right and just tonight I noticed an air sucking type noise from the engine bay near the air filter but it isn't the airfilter itself, it seems to be coming from further towards the rear and lower down. This leads me to think vacuume leak, or maybe fuel pressure regulator, or the pump. But I'm not the most experianced. Also no check engine light and it does work. I'm sorry if I've been all over the place I'm just trying to describe as much as I can. Other than the aforementioned symptoms it runs great, no stalls, idle is stable, goes smoothly from a warm idle (that very first mark above 0) to 7000. So I hope I've given enough info. Thanks in advance for any help

 

[jameskroth043084]

I would honestly replace all vacuum lines

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[HeX]

With that much mileage, replacing all the vacuum line definitely wouldnt hurt. Start by inspecting them all. Perhaps look up a vacuum line diagram so you know what hoses to check. YouTube has several videos on how to test for leaks using Carb cleaner spray. I'd also inspect the fuel injectors and consider replacing or refurbishing them (OsideTiger.com did a great job on mine).

 

[soufigured]

Oh okay, I can check the vacuume in the morning, and injectors were on the list when I replaced what I did, I just couldn't afford them right away. I think while I have the hood up tomorow it wouldn't hurt to look at the iacv and fast idle valve as well. Some reseaching pointed me that route. But I want to cover as much as possible. Thanks for the advice and I really hope it can help

 

[soufigured]

well i checked the vaccume and was un able to find any leaks. but ive developed some other symptoms leading me to believe the oil pump is shot. could that possibly have cause any of the prior issues? ill be getting a new oil pump tomorow