Toyota Trucks--1986 to 95 w/22RE Engine--Intermittent Misfire.
You may run across one of these vehicles with an intermittent misfire that seems to affect some or all cylinders. Your basic diagnostics for ignition reveals nothing, while fuel delivery seems to be OK. It seems that these vehicles have problems with wiring harness splices that are located under the intake plenum on the passenger side of the engine. These splice problems usually result in voltage drops on the power side of the fuel injectors. Unfortunately, only one injector can be accessed without removing the plenum. So, if your diagnostics lead you nowhere, try this tip. First, the upper intake must be removed. Next, unplug all of the injector connectors. Using a test light consisting of a #4651 two-pin headlamp, check for power at the injector power side of the connector. You can do this by grounding one terminal of the headlamp to the battery negative terminal, while connecting the other terminal to the injector connector terminal with either the yellow or blue wire (for 1986 to 1988), or, the black wire with the red stripe (for 1989 to 1995). With the ignition key in the "on" position, the test light should illuminate normally, Be aware, that on the 1986 to 1988 models, the light will illuminate dimmer than normal due to the dropping resistor in the circuit. While the light is illuminated, its a good idea to give the harness a good wiggle. If the light's brightness changes, you've found the source of the intermittent misfire. The light's brightness should remain consistent for all four injectors. If you find one splice that's bad, it's a good practice to open the harness and repair all four, even if they test OK, in order to prevent a comeback. While you have that plenum off, it wouldn't be a bad idea to clean that throttle body.
*Just the article that enlightened me to injectors mis-firing and not firing at all. But what do I know??? My 4Runner's been driving down the road after resoldering all the injector splices....2 years now??
~Darin <img src="/forums/images/graemlins/baby.gif" alt="" />
