Replaced tps on 96 aspire eng 1.3still surges then stumbles and dies after warm up whats the problem?

Answer 1

This problem could be attributed to a malfunctioning Idle Air Control (IAC) Valve. This device consists of a temperature-controlled idle air bypass valve and an electrically actuated solenoid to control the flow of coolant through the device in order to regulate idle speed. I know the valve is supposed to admit idle air when cold and divert it when hot, unless the solenoid is activated by the PCM. I assume correct operation lowers the temperature by limiting the flow of hot coolant through the valve once the engine is warm and under load. A wax pellet is used for thermostatic control of the air flow, and can be checked on the car by attempting to blow air through the inlet off the main air intake using a hairdryer and ice to artificially heat and cool. Electrical problems could occcur either with the solenoid or insufficient voltage from the PCM. I believe it is supposed to be at least 11 volts. The PCM is supposed to respond to loads caused by the transmission, Power Steering, lighting and climate control systems based on the positions of their individual switches and relays, so that any one of these could present a problem as well. The valve is mounted adjacent to the throttle body using four studs and nuts and cleaned with a solvent safe for coated throttle bodies, as well as the throttle body itself once the valve is removed. The solenoid is the cylindrical component attached to the valve body using one center-pinned Torx and three Phillips screws. Having said all this, I have found that taking the above steps may not lead to a solution of every idle problem, but nearly always results in improved driveability of the car.