I own a 2002 Toyota Camry LE V6 with 158000 miles. Lately it's been having a bucking/surging problem when I accelerate between 2000 and 3000 RPM. It did the same thing about 3 years ago due to a faulty oxygen sensor. I replaced it and the car has ran great since, but now it's doing it again. According to my scan tool, all oxygen sensors seem to be functioning normally. Though last week there was a P1410 code for an EGR circuit malfunction that went away the same day. I had replaced it today, since it did look in pretty bad shape, and cleaned the throttle body entirely, plus made sure all wiring and their connections weren't broken or loose. It ran OK for about half a mile and starting bucking again upon acceleration. There are still currently no codes. Problem started with no warning about a month ago.
My car has 158000 miles.
My car has an automatic transmission.
Try and road test the vehicle with the EGR valve vacuum line disconnected and plugged. Your check engine light may come on for the valve being disconnected but you are just testing for now. If the problem goes away then you know the EGR system is causing a lean condition in the engine causing the surge. Try and clean out the EGR passages and the EGR temp sensor of carbon. Try de-carbonize the intake and throttle body then clean the injectors. This should fix the problem. If you want a qualified technician to diagnose the problem, then you can contact one through YourMechanic to do this at your home or work.
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