The light engine turned on a few days ago and I got it scanned saying P0171 which they told me that I needed to replace the intake manifold gasket. I was going to do myself but then I couldn't do it because of the position of the screws. So I was going to buy an extension and then It turned off while driving. And the car has been shaking.
My car has 155000 miles.
My car has an automatic transmission.
Hello, thanks for writing in. The P0171 is an indication of a lean mixture, which can be caused by an air leak in the intake (as you were advised), a borderline engine temp sensor reporting a warmer engine temperature than exists, or a weak oxygen sensor. (There was also a Toyota Technical Service Bulletin which addresses "lean running issues in very cold climates" - #228497.)
If you need assistance with this repair, I would recommend having a rough idle inspection completed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.
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