2002 Accent major issue. Help!

[staggerlee917]

A few days ago, my Accent (2002, 1.6L) starting having a major misfire issue. Getting codes P0300, P0302, P0303. It had misfired slightly in the past (always after filling tank) and gone away quickly.
The coil pack was replaced about 2 years ago due to a starting issue. I replaced the plugs and checked wires, with no change. I also changed the fuel filter, still no change.
In the process of doing this work, I noticed white smoke from the exhaust, which gets worse as the engine warms up. I know this indicates a head gasket issue. I drained the oil to check for coolant, but all was well there. I did a compression test, and all cylinders are giving a consistent 230-240 psi. Pulled the radiator cap to check for bubbles, and there was a few small bubbles, though nothing major. I'm almost wondering if they were just caused by misfire vibrations.
I'm still suspecting the head gasket, but I'm not 100% sure... due to the only telltale sign being the white smoke.
I have limited funds, so I'm trying to do my best to diagnose and not just throw parts at it. I'm running out of ideas.

[staggerlee917]

Nobody?
I'm stumped and could really use some help...

[Barnyspup]

I am not the expert on this, but do this
Google search: Coolant Leak Test


Jim

[tedav]

Check for Vacuum leaks. Fuel Pressure. Voltage of electrical system/battery. Voltage drop across system. Grounds (electrical) are solid. Crankshaft Position Sensor could cause this also.

Do you feel or hear the engine missing?

It looks like cylinder 2 and 3 are on the same coil pack. 1 and 4 are on the other. Can they be switched?

Attached info from hmaservice.com hope it helps.

[staggerlee917]

I have a combustion gas test kit on the way. I'm told it's the quickest way to diagnose head gasket issues.
Is it possible for the crankshaft position sensor to fail without giving a code (P0335)?
Also, when I pulled the plugs, they were all pretty black (running rich). I'm guessing the O2 sensor will need replaced as well. The new plugs started turning black after a very short time.
The thing that puzzles me the most is the white smoke. From everything I've searched and read, this really can't be anything other than burning coolant (which would explain the O2 sensor failing). I find it strange that I haven't shown any other symptoms.

[staggerlee917]

Combustion gas test came back negative. Fluid stayed blue. Ruling out head gasket.
Is there a way to check crankshaft position sensor without replacing it?

Have a new timing belt kit, going to go ahead and do that anyway... it's about time for it.

[staggerlee917]

Also, plugged vacuum gauge into brake booster vacuum fitting on the manifold. Getting about 14-15" at idle.

[tedav]

My experience ( this is a 98 with 1.5l) with the CPS was it was intermittent and no code, causing hard starts especially when hot, and stalling. I removed the sensor and cleaned it and that improved the situation somewhat but I replaced and solved the issue completely.

Could the smoke be oil? Blocked/bad PCV valve or the valve cover clogged where the PCV draws vapor?

[rocket65]

Hey dude I had a very similar problem in my accent it turned out to be the valve at the air intake manifold. This runs to the fuel tank sucking out vapours from the tank. The valve was stuck open and was continually sucking air from the tank. When I filled it up it was sucking a rich air mixture making it run like crap. It backfired and had white smoke coming from the exhaust because of the rich mixture. Hope this helps good buddy.