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Q: recently my Safari started "hesitating" or " shifting" roughly when shifting at low speeds. doesn't do it all the time

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My safari recently started "hesitating, or "stumbling" when shifting thru the lower gears, or maybe it's not shifting properly. doesn't do it all the time. not sure if its an engine/ ignition problem, or transmission shifting problem, only seems to do it when shifting. Went to auto Zone had them run the code scanner came back w/ PO300, multiple random misfires detected,PO102 MAF sensor low freq., PO128 ECT sensor below Thermostat regulating temp. their printout suggested most common problem bad Dist. cap(& rotor) - replace not sure if it's that Because: van runs great at highway speeds,idles fine even runs fine at low, med speeds seems to only stumble when shifting. I also recently replaced Radiator, and put in lower temp(160 Deg) thermostat. wondering if that lower temp that it stays at could because of that PO128 low temp code be making the 'puter screw up the ignition timing and causing the "stumbling?" I mentioned? this started after that, but I also went on a 600mile trip

My car has 170000 miles.
My car has an automatic transmission.

Hi there. Many electronically controlled transmissions are computer controlled. With that said, the input signals for the engine can have a direct affect on the transmission behavior. Do no rely on scan tool recommendations because it is just that, a recommendation and not a diagnosis. Think of the scan tool you witnessed as a tool to sell parts, nothing more. A capable scan tool provides more than codes; it provides live data to the technician to aid in the diagnosis. When the computer sees an operating condition that is out of specification it sets a code; it does not know what or why, but only that it is out of spec. The code leads the technician to the system that has the fault; it does not diagnose it. Before you do anything, have the battery tested. A bad cell or low state of health can wreak havoc on an electrical system. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several technicians available that can assist you with a check engine light inspection and a car is shifting hard inspection.

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