1998 Chevy Silverado 1500 Rev high smoking

[dmbennettsr]

I have a 1995 K1500 with 5.7 L. It will run at higher RPM but will die as soon as I let off of the pedal. If just started and let run without giving it gas it will run for a few seconds and then die. It is harder to start than normal. It just started this today and yes it does have gas in it! HA!

[Havrom]

Sounds like you have a very bad vacuum leak. Engines will not idle with a vacuum leak, but run fine when on the gas. Spray some brake fluid around. When you hit the vacuum leak, the RPM will jump. Be very carefull though, since brake fluid is very flamable. So if you hit anyting in the ignition system- coil, cap and rotor, plug wires- it WILL burst into flames !

[tnb]

I went to crank my truck and it reved up high the rpm went up to 4,000 then shut off and started smoking. I have replaced my IAC valve TPS sensor cleaned the throttle body and cleaned the massive air flow. Need helping trying to figure out what is causing the truck to rev up high and then shut right back off

Thanks

[carriedi]

you should hook up a scanner and look at the data stream before you start it up. Then look at it and if you can record the data stream so you can see what is happening to the engine. A large vacuum leak?

you already spent money on parts that didn't fix it, before you buy more parts find out what is going on. Is the IAC reading too high? Is the exhaust showing too lean? TPS reading within spec? You can see so much in the numbers