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Chris (aka-Moose)
Chris (aka-Moose), Auto Technician
Category: Toyota
Satisfied Customers: 828
Experience:  16 years of experience
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Corolla: 2000 Toyota Corolla 4 cyl automatic. P0171 code. Cleaned

Customer Question

2000 Toyota Corolla 4 cyl automatic. P0171 code. Cleaned MAF, Cleaned injectors. Scan tool shows both O2 sensors switching fine. At idle the fuel trims are perfect, but as soon as you give it throttle, the long term trim jumps to 35 - 39% Short term is normal. Checked for misfires, fuel pump pressure and vacuum leaks. All ok.
Submitted: 1 year ago.
Category: Toyota
Expert:  Skyvisions replied 1 year ago.
How many miles and what is the compression?
Customer: replied 1 year ago.

164K and compression is 190 across the board

Expert:  Skyvisions replied 1 year ago.
Did you check the Vacuum at idle (21 to 19 in.) is idle and when driving is the fuel pressure dropping below 30 psi under load? Are you 100% certain there are no vacuum leaks? Do you have access to an oscilloscope?

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