737IP

94 Toyota truck, 4WD, 3.0 engine. The engine makes a grunting noise when I let off the gas. It is coming from the passenger side near the valve cover. Any ideas?

Thanks for the help.

Inferno451

It's probably a sigh of relief, especially it it's high mileage.

737IP

Yep. Could be. 206,000 miles.

stanprophet

Is the PCV valve anywhere near that VC?

737IP

Im not sure. I will have to look. That is a good idea though.

stanprophet

Im not really familiar with the layout of that engine, It has been many years since I have worked on one.

I have heard many PCV valve's make some strange noises.

Hey it is a quick easy check!

Xeo

Yea the pcv is on the passenger side valve cover, thing is the whole plenum has to come off to get to it.

Gamefreakgc

This was just posted about the PCV valve: https://www.yotatech.com/forums/f116...cement-266038/. Not worth your time.

I've never heard one "grunt". They usually rattle or hiss if the plastic is leaking.

Old engines make weird noises. Took me a while to get used to them on my truck with 280k miles, until I realized that it's not hurting anything and runs just fine.

scope103

I'd say it's the PAIR valve (80% certain, but worth a look). The sheet-metal cover is held on with four Phillips-head 5mm screws, and at exactly 206,000 miles one or more will get loose. Then the cover vibrates. Usually a "buzzing" sound, but your truck might be tuned to a different key.

Hard to get to in the best of circumstances, but you might be able to do it with a stubby screwdriver (or maybe a Phillips bit in a 1/4" ratchet). If you need to replace a screw (they don't hang around for long once they get loose), consider using a hex-head bolt. Much easier to reach.