In order to extract the best performance and economy from your engine it is essential that it be properly tuned at regular intervals. A regular tune-up will keep your Toyota's engine running smoothly and will prevent the annoying minor breakdowns and poor performance associated with an untuned engine.
All Toyota Pick-Ups use a conventional breaker points ignition system through 1974. In 1975 Toyota switched to a transistorized ignition system. This system was much like the previous system with one basic difference; instead of the breaker points switching the primary current to the coil on and off, they triggered an igniter which did it for them. This igniter contains two transistors and an assortment of resistors which together serve as a switching device to turn the coil primary current on and off. The advantage of this type of circuitry is a reduced current through the distributor breaker points, thus prolonging their expected life and reducing scheduled maintenance. The transistorized igniter is found next to the coil on the right fender panel (as you face the truck) in 1975, and mounted on top of the coil in the same location in 1976-77. In 1977, a few models sold in California came equipped with a fully transistorized electronic ignition system. In 1978, this system became standard on all models.
A complete tune-up should be performed every 15,000 miles (24,000 km) or twelve months, whichever comes first. This interval should be halved if the truck is operated under severe conditions, such as trailer towing, prolonged idling, continual stop and start driving, or if starting or running problems are noticed. It is assumed that the routine maintenance described in General Information & Maintenance has been kept up, as this will have a decided effect on the results of a tune-up. All of the applicable steps of a tune-up should be followed in order, as the result is a cumulative one.
If the specifications on the tune-up sticker in the engine compartment of your Toyota disagree with the "Tune-Up Specifications'' chart in this section, the figures on the sticker must be used. The sticker often reflects changes made during the production run.