Just ordered an OBDII sending unit to link up with my Ipad. I should get it on Saturday.
So I cleaned the MAF and reinstalled the stock airbox, and the symptom persists. Got in the OBD 2 tool and got some real-time data, but for some reason, though fuel pressure is an available PID in both of the apps I installed, neither will give me any reading on that, so I am still in the dark. No other readings perceptibly changed when the shuddering started. Again this weekend the car got really bad, shuddering even at low speeds, but after parking it for a ay I had to drive it because my wife had our minivan, and it barely shuddered at all.
I still suspect a bad axle. As cigroller said earlier, bad CV joint symptoms can be variable, so the fact that the shuddering got bad at low speed and then temporarily improved is not necessarily inconsistent with a bad CV joint.
I will be surprised if you find anything wrong with the engine.
I’m going to double-down and say both axles should be replaced. The variability of the shuddering can be caused by the position of the axles relative to each other. Their individual shuddering can tend to amplify or cancel each other.
“I also have replaced the IACV and MAF due to a CEL”
You didn’t post the codes, but I’d say there’s a fair chance the MAF failed BECAUSE of your aftermarket oiled air filter . . . K&N, I presume?
I recommend you ditch the K&N and go back to the stock configuration
I just looked at your owner’s manual and maintenance guide online. You’re changing your oil too infrequently.
Bottom line . . . Your engine requires 5w30 conventional, and it gets changed every 5K/6 months, whichever comes first. Using synthetic is fine, but Toyota makes no mention of extended oil change intervals.
Was it your idea to go to 10K intervals?
If somebody told you to do this, they’re wrong.
No offense intended to anybody
I have put less than 10000 miles on the car in the just over a year I have owned it, and I changed the oil right at 6 months ago, so I should be still within the manufacturer’s guidelines. I got the 10000 mile number from Toyota owners blog with many contributors specifically for my car. It is also what I have been told in the past regarding synthetics. Also, I don’t think the MAF was actually bad. They merely replaced it because they still got the Idle Air control system code after changing the IACV. Of course, I still have the P0505 code on-again off-again, with the new IACV and new MAF, and I changed back to the stock airbox. Shuddering has gotten really bad now, and I’m going to break down and take it back to a mechanic for diagnostic.
Good luck with the diagnosis. We will be curious to hear what the mechanic finds.