Toyota Repair: Rough Idle, throttle position sensor, digital multimeter

Question
I got a 93 toyota pickup with a 4 cylinder. Its got a really rough idle all the time.  It will stall out sometimes but most of the time right after you first start it up unless you give it alittle gas.  Is there away to adjust the idle or do i need to check the distributor

Answer
Yes, there is a way to adjust the idle. There's a slotted idle screw located on top of the throttle body. You will experience stalling at start up after running your truck to operating temperature because when you shut the engine off, the engine gets hotter than operating temp. Therefore the idle gets affected until the engine runs for a few minutes circulating the coolant and cools down. If there's damage to the distributor or the dist. cap, it can cause stalling as well. Sometimes, the throttle position sensor can cause a rough idle due to age and wear. In your case, you have a '93 4 cylinder which tells me that it's a 22R-E engine. Those engines are well built, but the actuators and sensors can act up and affect your drivability. If you need to test the throttle sensor, borrow a digital multimeter and back-probe the wiring that's attached to the sensor. Keep in mind that TCCS systems run on low voltage (0.5v - 4.5v). This sensor should read a steady increase from 0.5v at closed throttle to 4.5v at WOT (wide open throttle). If there's any deviation from the above mentioned activity, you will have to replace throttle sensor because they're set from the factory. You can adjust them, but it's not worth the trouble and will void any warranty you might have in the vehicle. I would guess at this point that there is no warranty based on the age of the truck unless you bought it from a used car dealer.