03 accord 2.4 problems
 

I bought a used 2003 accord 2.4L manual with 172,000 miles. CEL was on for cat. car was loosing power after 2800 rpm but the symptoms would come and go. I replaced the cat and car run fine for maybe 3,000 miles. (it still burns a quart of oil every 300 miles or so. but does not smoke or have any major leaks.(@176,000 miles) 2 weeks ago I was driving down the interstate at 70 mph. I sped up to about 100 mph @ maybe 4000 rpm in 5th gear and held it there for about 2 miles. after i slowed back down my CEL started flashing then as i got into town i noticed my engine idling really rough. i checked the oil and it only had about 1 1/2 quarts. it was throwing codes for 1 and 2 cylinder misfire,random misfire. I replaced the ignition coils and spark plugs with no effect.(cylinder 2 is not firing i think, the plug was black and oily, other 3 are white crusty). I do have spark coming from the ignition coil so im thinking maybe bad cylinder? car is still idling rough, bad gas mileage,no power. I then swapped the injectors from a 05 TSX 2,4L. ,replaced valve cover gasket(it was leaking). still have not fixed the problem. I had the CEL checked again and got codes p0302 x2,p0301 x2,p0303 x2, p2645(rocker arm actuator control). I changed the vtec selnoid and still no effect.. car is now jumping rpm at idle)700-1500, like its slowing down then trying to catch up. and seems everytime i stop to turn in somewhere the car just cuts off..any ideas?( the CEL is flashing and not staying on constant now) please help?? im thinking im gonna have to replace the engine

Compression test the engine. If those numbers are in range.

Pull the connector from the coils one at a time....pull number #1, does the idle change or stay the same....reconnect number 1 and move to number two, ect. At some or any point when you do this does the idle "not change"?

^^thanks for the advice. I will try what you said tomorrow and keep you posted.

Let's us know the results.

Where I'm going...Honda's seem to get confused, when one cyl has an issue with a miss-fire it will often show up as multiple cyl's. Oil in the plug tubes could have taken out one of the coils giving the P030X code(s).

I don't see a P2645 listed for the engine year you have so I'm saving that for later - figure out the P030X first.

Compression test
 

Well I have bad news.. cylinder 2 only had 48psi, other 3 had around 150psi. I'm wandering if it's possible that I have a blown head gasket into an oil port around cylinder 2 ? Also I started the engine,while idling I removed the oil cap and it had a bunch of air blowing out..like you could hold your hand a foot from the hole and still feel the blow back. I removed the valve cover and checked the gap in my springs. All within specs. I'm still driving the car, it just runs like sh** ,horrible gas mileage, CEL is flashing, and the engine dies every time I slow down to stop or make a turn but it starts right back up I just have to ride the clutch a little to keep the rpms up

Loss of compression can be from worn rings, bad valve(s), a bad head gasket, craked engine block, cracked cylinder head, or work engine bore. The next step would be a leak down test on the #2 cylinder.

You only really need to get #2 to the top of the compression stroke, and put air pressure on the cylinder. Then you need to figure out if air is coming from exhaust pipe (exhaust valves), throttle body (intake valve), oil fill cap (ring issue), or radiator (head gasket).

From your description of pressure from the oil cap, the piston is not sealing. That can be from a cracked cylinder, cracked cylinder head, or worn/damaged rings.

You can also try pouring a few tablespoons of oil into the #2 cylinder and retesting the compression. An increase in psi would indicated an issue with the piston sealing.

Thanks I will try that soon as I get a chance. I talked to a friend and he thinks it Might be a blown headgasket but either was im thinking my next step is to park it and take the engine apart or..possible doing an engine swap? depending on what I find. I can get a whole used engine with alot less miles for around 5oo$.

Definitely verify your problem before proceeding.

Swapping the engine with a good used engine will be cheaper vs repairing. I'd definitely request a compression test and a leak down test on the used engine to verify its in good condition.

Do you know if all the honda 2.4L ivtec engines are the same? Im wandering what all is compatible as far as doing an easy engine swap.

I'd recommend an identical swap to make your life easier. You can go to a site like car-part.com and enter your vehicle info. It will search junkyards that subscribe with their service for motors that are identical. You can sort by price or distance. The years of accords listed are identical.

I'd guess the 03-07 accord engines will all work.