Chevy 1999 Silverado 5.3L V8 Vortec.
Question = where is the intake air sensor located underneath my hood at?
The intake air temp sensor is an integral part of the Mass Airflow Sensor (MAF)
It cannot be replaced separately. The MAF is the large sensor right out of the air cleaner box.
1990 Chevy Caprice Service engine soon.
Question = I have a 1990 Chevrolet Caprice with a 350 Vortec engine, and 400 trans. I purchased it last week and I'm having some problems. The car cranks up fine. Once i run the car for a good 20 minutes and it warms up good it starts to cut off if i take my foot off the gas. Also once it warms up it starts to sound like a diesel engine. When it cuts off, it cranks back up, but it will easily cut back off again. It gets worse. Also it skips. What should i do and where should i start. The guy i purchased this car from was into racing but i want it to be more road suitable.
You'd have to find out if he did any modifications to the engine to make it run differently. If he put a bigger camshaft in, or changed the timing and/or fuel delivery, that may just be the way the car is going to run. If it's still stock, you could have a timing issue such as a worn timing chain or gears, distributor or ignition problem such as a faulty ignition module.
An ignition module usually starts to mess up after the engine gets hot, like you describe, so you may want to start checking there. You should also check for any trouble codes stored in the computer, that may help in diagnosis.
Silverado Intake Air Temperature Sensor Location