I have a 99 tahoe 5.7 v8 and I change the spark plugs and change the oil, trans oil the gaskets the battery is good the starter and alt. it's gettin Fire but not starting wat can this be

If it's cranking over for ever and not firing, it sounds like your fuel pump is shot. Have someone turn the key to Accessory and see if you can hear the fuel pump hum. Take off the fuel cap and put your ear to the opening and see if you can hear it hum. You may want to check your fuse and relay also.

I check the fuses and relay they are good and when I turn the key I can hear the pump could this be my timing chain two pple came look at it and one say it's the fuel pump and the other said it's the timing chain don't want just keep buyin parts and it's not the problem

And it's firing it just don't won't start

I doubt it's the timing. If the timing chain broke, you never would have gotten it in the door yard. You would be dead on the road. Have you pulled a plug wire and checked for spark yet? The fuel line has a check valve next to engine.Looks like a tire stem. Have you made sure that you are getting fuel to the engine?

I think I'm not get fuel to the engine and yes it's gettin spark how do I get the fuel to the engine

It's like it want to start but it's not

If you find that you are not getting fuel to the engine, your fuel pump may be bad. Or you may have a bad fuel pressure regulator. Have you tried spaying anything into the throttle body and see if it tries to start?

Buy a cheap fuel pressure gauge and do this test: This way you will know for sure. https://www.youtube.com/watch?v=53w5v7CHpCQ

Sound like the front crank timing sensor on the front pulley. My sister in law's Tahoe (97) had that happen just out of the blue.

They have a crank shaft position sensor that's wat you talking about

I'm getting pressure I check it

Okay, so if you have good pressure that will rule out a bad fuel pump and regulator. You can try replacing the crank sensor like Timbo991 suggested and see if that works.

Ok thanks I'm bout to go get it now and another thing when it was running it was only ship in first and second but I know the transmission good can that be the crankshaft sensor

Not sure.

Or the tPs

The transmission usually shifts in accordance with the vehicles RPM's. A bad TPS could have an effect on shifting by sending bad data to the computer. Have you made sure the fluid level in the tranny was good?

Yup the level is good I will take the tps off and go have it tested

Just a thought...if your vehicle has a neutral safety switch, that may be bad causing your no start condition.

Check your wires to the distributor cap. They may have come unplugged

I'm having the same problem. I done the check on the valve and gas comes out. I can spray starting fluid in the throttle body and it cranks but the shuts back off after a few seconds

I have 2 I have a clinking dink sink sound sometimes when I slow and then take off is thi the transfer case or whatand my 2hi light doesn't stay on a