1994 4Runner
eBay headers
EGR deleted
Flamethrower injectors

In the middle of driving just fine, engine starts to stumble, weak throttle response, at stop idle began bouncing, no smoke

thanks for looking

 

Anybody?

 

I'm not sure what you hope for us to learn from a video, but if the noise I hear is the one you're concerned about, my guess is that it has something to do with the fan.

Get the tube from a roll of paper towels, and use that as a "stethoscope" to localize whatever sound concerns you.

 

You think the erratic rpm (falls so low as to stall), engine stumbling (sort of misfire), lack of throttle response (press on gas pedal has little effect), sound of marbles in the engine has something to do with the fan or fan clutch?
Try again.

 

 

Broken valve spring? Valve stuck open?

 

Definitely either a broken spring or valve. Either way, the head is going to have to come off to fix it. If the valve stem broke or the keepers came out, there is a chance the valve may have made contact with the piston. Unfortunate no matter how you look at it. Guess it's time for that 3.4 swap, eh?

 

A broken valve spring shouldn't be TOO hard to fix, depending on collateral damage. A stuck valve is often just a matter of replacing a valve guide. Probably a machine-shop job, as you're supposed to heat the whole head to expand it to put the new guide in. The 3VZE is non-interference, so a stuck valve doesn't necessarily do damage.

But you are correct: there's only one way to find out. And if you're leaning toward installing a 3.4, sure, this could be all you need.

 

True. I guess I'm speaking from experience a bit, I've never seen a stuck valve. It's always been a spring or broken stem at the retainer slot. You're right though, if the valve is still retained, it SHOULDN'T make contact, but if the stem breaks and the valve drops, well...