Hi! I am at my wits end. I have an 05 5.7 v8. Several months ago my throttle warning light came on. Car turned off, started right back up. Did lots of research. No check engine light! Replaced complete throttle body. Did great for couple week. Then same problems happen. Needless to say I have replaced... throttle body, crankshaft sensor, camshaft sensor, accelerator pedal position sensor, then another crankshaft sensor because it threw a code for it, knock sensor. It will do good when it wants to. It seems like if I drive a lot in the day and the engine don’t have time to cool down all the way it messes up more! What am I missing? I’m out of ideas! Someone please help

 

9 times out of 10 your issue will be a vacuum leak under the hood. No code or check engine light makes this even more likely. There are main culprits, EGR VALVE, PCV, gas tank vapor PURGE VALVE and any other vacuum line or connection.

Get the hood up with the engine running and listen for a high pitch hissing sound, that's a vacuum leak. A complete computer diagnostic tool can tell you a vacuum leak is is present as well, but those are expensive, so use your ears. Locate the area that hissing sound is coming from. That is a big help identifying what might be the culprit.

The PCV is located at back passenger side of the engine on top. The EGR VALVE is located at the front passenger side of the engine down about halfway. The PURGE VALVE is located back against the firewall on the driver side between the engine and brake booster.

Nothing is more infuriating than the throttle body warning light failure mode! I know because I chased this problem for days, being forced to the side of the road only for a restart and everything was fine. Let us know how you're doing getting this resolved.