4.0 OHV knock

[lman]

So I started having some kind of a knocking sound, but I'm not totally sure where its coming from. It does not happen when the engine is at idle, or when I first start it. Its not very loud, I can usually only hear it when it echos off of something while I'm driving. If I rev it up while its sitting the knock doesn't start immediately, but it does knock. It doesn't sound metallic, so I'm not sure whats going on. Any ideas?

 

[JimRummy]

Is it a knock, tick or a ping? I've a random ticking occur immediately after flooring it to pass someone on the freeway, pulled off, and one of the dpfe sensors hoses blew off. Re connected and it went away. Check those hoses if you haven't already. Same as you it only made noise while driving, not idle.

 

[lman]

I guess its more of a tick. It only seems to happen during light throttle, such as driving in traffic. and it also seems to be worse at lower rpm.

 

[lman]

Don't know if this could help anyone or not, but ended up figuring out it wasn't anything in the engine. It was the EVAP purge valve. It is still functioning correctly, but is worn out and clicking loudly as it cycles open and closed. The sound was only happening after the engine got warm, and when the throttle was consistent, but was happening at all RPM.

 

[cp2295]

Weird, good info.


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