Hello,
This could be a problem with your vehicle's throttle body being dirty. When your vehicle's throttle body gets gunked up with "tar" looking substance, which is normal from air flow over time, the Throttle Position Sensor (TPS) has a hard time communicating how much the actual throttle plate is open to the Power-train Control Module (PCM) AKA,"computer". When the PCM gets varied or mixed signals it will go into "limp" mode to get it to a shop to be fixed. Engine's are essentially air pumps, as the air to fuel ratio ideally is 14.7 parts air to 1 part fuel(this is because at sea level the earth's atmosphere is exactly 14.7 miles high), so going lean, that is adding more air to the mix, is a sure fire way for internal engine damage.
I have included a couple of links for you down below:
https://www.2carpros.com/articles/how-a-throttle-body-works
https://www.2carpros.com/articles/throttle-actuator-service
Please go through these links and let us know what you find out.
Thanks,
Alex
2CarPros
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Monday, March 18th, 2019 AT 11:24 AM