Toyota pickup trucks have long enjoyed a reputation of reliability and long-lasting performance. However, that doesn't mean the vehicles are problem-free. Particularly due to computer sensors integrated into the engine systems, Toyota trucks suffer idling issues like many other car brands.
As part of federal laws and efforts to make cars cleaner, U.S. cars have increasingly had to incorporate a number of sensors to make sure emissions stay within legal ranges. The oxygen sensor and mass air flow sensor are two types that frequently get plugged with carbon deposits, which then can cause idling problems as bad data cause the pickup computer to erroneously change the air/fuel mixture to the engine in idle.
For those pickup trucks that use a carburetor (pre-fuel injection days), many Toyotas had an anti-diesel solenoid attached to the carburetor. This part is responsible for cutting off fuel when the engine began to keep running after the car was turned off. However, when the solenoid malfunctions, it can also kill the truck just when it's idling normally.
If the idle speed reads as being higher than an acceptable range, the engine control module in some trucks will react and restrict fuel. Then, the engine will do the opposite and suddenly increase fuel flow to compensate. The reaction is that the engine seems to surge for no reason whatsoever. The cause is an expandable pellet in a valve that reacts to temperature.
