Rattle under hood

All,

I have a 17' Taco and I have noticed a weird rattle under the hood when I am in either 3rd of 4th gear. I brought it to Tacoma and they did a TSB for a vacuum pump but that doesn't seem to have fixed the issue. It seems to rattle when gassing it when the RPM's are low. Anyone else have this issue?

Thanks

 

Manual or automatic?

 

Sorry, it's an Auto.

 

Sound like marbles in a can? That's usually detonation. If it's a deeper knocking sound, that's usually 'lugging' the engine. Both are bad, but have different root causes.

Experiment by downshifting manually at that low RPM and see if that 'fixes' it.

If it does, and you can repeatedly replicate it, at least you have something to show a technician on a road test.

 

Could this be the "stumble on acceleration" I've seen on here lately..?? There's a TSB

Search STUMBLE ON ACCELERATION

 

It def sounds like marbles in a can, that's prob the most accurate way to describe it.

 

If you are running the correct fuel, it shouldn't do that.

Since these things are automagical these days, the dealer will be your best bet for correction. My 'guessing' (and that's all it is) would be

1) trans not downshifting correctly to raise RPM a bit, there is a TSB that might be the cure.

2) the CPS out of spec

3) knock sensor out of spec

I'm not betting on anything here. But let us know what the resolution is please.

 

Will do, thank you.