My special lady's '01 Avalon with a billion miles (close to 300k but religiously maintained) has developed an intermittent stumble on mild acceleration like initial tip-in at parking speeds or occasionally highway cruising. It shows a CEL and, perhaps interestingly, both of the VSC lights when the problem occurs; CEL code is P1354, related to the VVT system.
Just wondering if anybody has a brilliant insight before I start poking at it.
Something in the VVT system has a little piece of sludge in it would be my guess, or a failing/gunked up solenoid valve. What kind of oil has it run for 300k miles?
EDIT: Also, is it babied or does it get wrung out to redline occasionally?
It has been fed synthetic since day one. I'm probably the only driver to introduce it to the top of the rev range, and only relatively recently in its life.
After spending a little time poking around a Toyota forum, it would seem your diagnosis is likely correct, as most people replace the oil control valves in each head to treat this issue (and this engine code).
The fun part is, now it's occasionally throwing misfire codes and running super rough at idle. But only intermittently, of course.
In reply to alex:
You mean like an engine that intermittently has a huge, advanced, cam in it?
Just a big, consistent stumble at idle. I believe the misfire code - it seems like one cylinder isn't firing. But it also seems to go away above idle. And of course this symptom comes and goes. Like this morning, totally fine.
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