I 4 engine knocking when hot ?

When my engine is hot and I stop at a red light. The engine rpm go down to about 700 rpm and the engine is running like a diesel !!! Like Knocking ??? at time the engine rpm go up a litle bit and it stop 1000 rpm. When it go down again the noise is going back. If I accelerate it make like a ratteling sound like a small diesel engine ??? Is it normal ??? (2010 Tacoma sr5 I4)
Everyting else is fine the truck go whell and all







Scuse My baddddddddd english

 

Normal gas 87 i think !!!

 

The engine run smouth, it push fine but when hot it does this bizarre diesel like sound ??? The truck as only 3300 km
Nobody as the same noise

 

I notice it last week when I was stuck in traffic. Engine hot rpm go down 700 rpm and clac clac clac clac clac....

 

It was at at operating temperature
Just when out and listen at the engine. It run like a baby...
Only when running for a long time and when it's hot outside it does it. The truck is not overheating. Weirdddddd

 

I would turn the A/C off and see if it goes away. If so, you may just have a noisy A/C compressor clutch.

Mine is a little noisy at idle and makes what some would think is a dieseling sound.

 

I notice the same thing out of mine - window down at a drive-thru with the AC on. Check that first, might not be an issue.

Mike

 

Yup...try turning of the AC mines does the same.

 

sometimes the throwout bearing will wear and do this also and when u push in the cluth it stops .while running the ac its add more engine stress and makes it louder . .id get it checked out tho your truck may have a faulty throwout bearing it should b quick with ur little mileage

 

Thanks I'l check the next time turning the AC off.