Troubleshooting help? Running rough

Hello . Im having an issue with my 2001 2.7 that I can’t seem to figure out. It started running rough and check engine light, only for short periods of time intermittently at first a month or two ago. It wasn’t too bad at first. It would like, loose half power for a few seconds, then restore back to normal. Then it got more frequent and would loose power for longer periods of time. Then progressed to running rough and shaking the whole time. I installed new Denso plugs and coils and no improvement. Also tried a few other new sensors maf and coolant temp. And injector cleaning… The codes on the scanner were p0300 & p0304 Any ideas what could be the cause? Thank you

 

Bump?

 

Next to impossible to diagnose given the information. It sounds electrical to me, any signs of mouse/rat activity in the engine compartment? You can start by wiggling the harness's that affect cyl #4 and see if you can reproduce it. You have done what you can do, unfortunatly you just might have to wait until it becomes a consistant problem.

 

Yes. That’s what I was thinking, like it’s not getting a good ground or something. I have checked and cleaned all the ground points in the engine bay. I also read somewhere that there is supposed to be a ground to the frame in the left rear near the shock mount but not sure about that because I saw nothing there. The problem was intermittent but now it’s constant,!always runs rough and big decrease of power. The check engine light stays on when I stop and starts flashing as soon as I start driving. Thanks for the response

 

I was hoping that maybe someone else had a similar problem and figured it out

 

Bump?