My 1997 chevy z71 will idel like a new truck but the second u touch the gas pedal it will either die out or it will rev to about 1500 -2000 then start back firing like crazy changed the o2 sencors the tps and it still will not run

sounds like ur fuel pump is burned out (broken impellor) get a new one.
of course she revs and dies if u pour fuel down the carby...duh.

does thr engine rev upwhen started than idels back down.try idel control switch and map sensor

I would replace the IAC air bypass valve, also I would have the fuel injectors cleaning service done by a dealer, not the pour in the tank cleaner, it doesn't work.

If the truck turns over, but will not start. The most common problem is the fuel pump. When you turn the key to the ON position, you should hear the fuel pump run for about 2 seconds. You may have to open the gas cap to hear it. If you can't hear it with the gas cap off, then that is going to be your problem. They are in the top of the fuel tank. And they are not real easy to change. You either have to drop the fuel tank or take the bed off. I personally take the bed off. It is a lot easier if you have a couple of people to help you. Dropping the tank is no fun at all. Plus it makes getting the ring that holds the fuel pump in a lot more difficult to get off.
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the idele speed control valve is not working properly

I'm having this problem now. Did you find out the solution?

Possibly bad tpos sensor

Bad idle air control valve

Bad maf sensor

Check the computer codes first before spending any more money on it

Also do a compression check

And check your valve timing and ignition timing just in case.

does anyone know where the throttle position sensor is located on a 1997 chevy Z71 truck ?

start bleding again from left to rigt all the way around.

timing belt slipped,bent valves, sorry