Rep Power: 0

I own a manual 03 civic ex coupe, strapped on cash and wanting to DIY. Got a few codes and symptoms, help would be appreciated.

P0300, 301, 302 (all showing up twice) P1259, P1457.
Acceleration is sluggish, fume smell in cab when idle, idling at 750-1750, jerking rarely, clearly leaking air pressure when accelerating from where I believe to be the downpipe off the manifold, donut gasket may be bad. After driving for 3 hours the car seems to turn into one of those battery powered childrens cars. If I let it cool down to air temperature it runs seemingly okay again. Oil is fine, tranny fluid is fine, checked all fluids. Clutch also started squeaking or creaking slightly but Im still shifting fine. I had one of my coil packs literally not even bolted in due to the previous owner using the wrong nut. I tightened it on with a lock and washer and the symptoms went away for a week. Check engine light comes on only rarely. Applied muffler cement around the manifold donut gasket and pretty much all symptoms went away for, ya know, 3 hours before the cement melted off.

Anyone have any ideas what my issue is? Thanks ahead of time.

 
Rep Power: 173

So, same codes or different ones?

There are probably stored codes in the ECU that only appear after a few on/off cycles.

That solved EVERYTHING?! Try a more permanent solution! New donut and bolts would be cheap and my next step.

 
Rep Power: 517

Oil consumption and neglect can lead to P1259 VTEC code when there's only about .5 quart remaining in the engine, and low oil level alone causes plenty of problems..... Is that the cause of your code? I can't tell from here. There are other possible causes, but lack of oil is the most common.

Oil consumption can lead to fouled plugs. Is that the cause of misfire? I can't tell from here.
You may have plug damage AND coil damage from someone leaving a coil incorrectly secured.

Misfire leads to cat damage,
cat damage leads to restriction/backpressure,
backpressure leads to the spring loaded joint trying to open like a relief valve.

Record freeze frame data if possible.
Erase codes.
Check and fill or change the oil as needed.
Make it run correctly first, without misfires.
If it has low power, unbolt the front spring loaded exhaust joint (engine will be loud) and see if full power returns with the exhaust opened up.
AFTER the engine runs perfect with zero misfires, you can then replace the catalytic converter if that is in fact causing an exhaust restriction, along with checking the rest of the exhaust for broken pieces of cat substrate..


P1457 won't make it run bad. Erase codes and see which codes reset later.

 
Rep Power: 0

Thanks all for the input. Helped a lot. So my solution was to replace the vtec solenoid, spray pb blaster on the flange bolts every hour yesterday until I was able to tighten it down firmly, and the last thing was improperly gapped spark plugs (2), and one spark plug was simply finger tight. Also minor thing gunk collected around the coil pack socket and was stopping 1 pack from being tightened correctly. My civic is good. Now for tires