Random Misfire Problem

Hey everyone, new to the forum and looking for some help. I’m not very mechanically inclined so most things beyond maintenance and upkeep are beyond me. I have a 2006 4.0L V6 2wd Tacoma. It’s throwing up a P0300 Random Misfire code. When you crank it up it shakes, sputters from the tailpipe, & acts like it’s about to stall out. Turn it off and crank it up again immediately and it’s fine idling, but once you get to 30 mph it starts vibrating. Also it only vibrates when pressing the accelerator. Take your foot off the gas and the vibration stops. I’m pretty lost as to the cause. I put 6 new NGK spark plugs in it last year and last week I put 6 new NGK coil packs in but the problem persists. Anyone else ever have this problem or any idea as to the cause then solution? Thankful for any input.

 

The closest symptoms I experienced to this was a plugged catalytic converter but I think you would see more codes than the one. A bad head gasket also fits the symptoms. Check the obvious signs - milky oil, exhaust smell in coolant, white smoke from exhaust, etc …

 

Thanks I’ll check it all out

 

Have you replaced the valve cover and spark plug tube gaskets? Pop a coil out and see if the tip is dry or covered in oil

 

2006?
MAF, fuel pump???
The mass air flow, you can purchase cleaners at any auto store.
Fuel pump/filter you'll have to drop the tank to check. I haven't had the opportunity to work on the fuel system of mine so I'm not sure if there's a place to temporarily plug a fuel pressure gauge in the line to check fuel pressure.

 

Haven’t replaced a valve cover or tube gasket. Was thinking about dropping the tank and installing a new fuel pump and filter and see if that does anything next.

 

It would be cheaper to let a mechanic trouble shoot the issue instead of throwing more parts at it

At least check the fuel pressure before condemning the pump

 

I’m sticking with the tube gaskets

 

Turned out to be a big vacuum leak. Found out right before I dropped the tank.