Why is my 2007 subaru tribeca having Shaking issues

Take the car to a shop and have the codes read with a scanner through your OBDII port. The shop should be able to tell you where to start. If you don't trust them, ask for the codes and run them thru Google. There are a ton of Subaru car forums where you can post the codes and receive help. Good luck!

Exactly! Check to see if a vacuum hose is disconnected, or look for a loose MAF sensor area clamp. Post CELs here.

Thank u and Hello yes i went to autozone and the codes came that the 1,3 ,6 cylinders are misfiring but i just bought all 6 brand new ones and put them on yesterday

Clear (erase) the codes and start over again, reading the next batch. Perhaps you didn't push the boots on the plugs fully? I trust you used any decent correct iridium plug.... Given your misfires involve both heads is indeed intriguing. Keep posting new info.

Hello so i got a new problems with my subaru now a few times that it starts shaking the check engine light is blinking and other times its not shaking and the cel is soild and also it hesitate to accelarate? What is happening now please help

Still have misfire codes?

yes p0301 p0303 p0306

So BOTH heads, eh? Check plugs, wires, coil-pack again. If all is ok maybe try to power clean the injectors after removing them. If no-go you may have to drop the exhaust and see if valve sleeves have fallen. You might even have burned valves, alas....