Engine Shudder

mine has a subtle shudder like you described. I determined it was the rear bed liner rattling against the bed when there is a slight load on the driveline. TO check this, put the truck in gear (auto trans) then the e-brake on, then walk to to the rear of the truck and push against the bed liner etc to see if you can eliminate the rattling. Inside my cab it sounds cab, almost like it could be transmission related but it is definitely the bed liner. I have also heard that the rear springs can cause quite a rattle throughout the entire truck.

Good luck

 

Alright, after a few weeks of test driving I feel confident the problem has been solved. I finally gave up and took the truck into the toyota dealer service center and had a mechanic take a look at it. I ended up having the main center bearing on the drive shaft replaced. This repair made no sense to me but it eliminated 80% of the problem. While I was there I bought a set of toyota brand spark plugs and swapped them out with the ones I had previously put in from autozone. This seemed to take care of the remaining 20% of the issue. As of now Im not having any issues. Thank you to all the people who have offered their input!