I have a 2004 Ram 2500 5.7 hemi, it idles real rough. Issue has been happening in and out for a few months, now has been happening constantly for a week. Only occurs when truck is in Park. As soon as I shift into reverse or drive it goes away.

I have codes P0300, P0456 and P0152 coming up.

I have changed spark plugs and right side upstream O2 sensor and the problem is still there.

Thinking it could be fuel injectors or EGR valve?

Please help

 

P0300 random misfire's 0456? Evap system? 0152 bank 2 sensor 1 02 heater circuit. If you can swing it replace all 4 02 sensors. The others will fail soon. Ego valve issue will give you a code. Clean the throttle body and put some sea foam in the tank.