The car hesitates at take-off, RPM's jump up and then back to normal as car moves. No issues on highway unless I have to stop. One mechanic says catalytic converter, another says Throttle Body Assembly. I asked if TBA can just be cleaned and was told no because computer is not receiving message. I took it to Autozone and the codes said a small air leak but the 2nd mechanic said those codes were about emissions and nothing to do with car performance in hesitation and that if I don't fix TBA I will press pedal to the floor and not move. I did change front and rear air intake hose recently. One was cracked. I don't know which to believe, either is expensive, not sure if car is worth it but I love it. Would be really upset if fixed one and it was the other that needed to be done.
My car has 218000 miles.
The catalytic converter has nothing to do with the symptom you are describing and, in any event, is easy to rule in or out as a "cause" of any malfunction. You simply measure exhaust back pressure with a gauge, compare converter inlet and outlet temperatures and compare upstream and downstream O2 sensor wave forms and you’re done. Although a mechanic would have to test for himself/herself, if RPM’s are rising steadily, and smoothly, and yet the car doesn’t move accordingly or immediately, in "lock step" , that suggests a transmission problem. Transmissions have clutches. Pressure in the hydraulic circuits that operate these clutches has to reach a certain level before the clutches will hold. If you have a hydraulic leak in a transmission, rising RPM’s helps to overcome that as pressure builds. But, it is also possible that you have an issue with the throttle position sensor which, if malfunctioning, could affect transmission operation. The EVAP system leak referred to in the codes should be repaired and the codes erased. You don’t need to worry about buying this part versus that point at this early stage. What you need is an EXACT diagnostic. If you request a certified mechanic from YourMechanic, you will get an exact diagnostic and then you will know what your repair cost is going to be. The appropriate diagnostic to request is a hesitation diagnostic. If you request that, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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