the90am

So I've been having an issue with my '06 xa 3.0. It's automatic with 125,000 miles. Every time i accelerate up between 2,000 and 3,000 RPM it makes a crackling sound. It's really difficult to explain. When you accelerate uphill it's much louder. I've taken it to the dealership and they can't seem to locate the problem. They tell me it's difficult to diagnose a sound when there's no check engine light on. Also, the engine some days has a rough idle and hard time cranking. Rarely the engine will almost shut off dropping just below 1,000 RPM and then shaking to stay on. I don't want to wait until the engine completely fails or something worse!
Maintenance has been perfect. Recently had a full transmission fluid exchange, brake fluid exchange, engine coolant flush, fuel line cleaned, new engine oil, new front struts, and tires. I always use top tier fuel as well. If anyone has some guidance of what to look for that would be awesome! I had one suggestion that it could be the time chain which I hear is rare for it to begin failing. Also the heat shield was checked and it's fine. Also new muffler and frame along with rear bumper.

mb2008

Have you ever cleaned the MAF sensor?

Yajaira@Scion

Hey The90am,

Have you tried having another Scion/Toyota dealer inspect your xA? They may be able to duplicate the noise and provide a second opinion.

jct

could be your knock sensor gone bad and what your hearing is the engine pinging

jct

try filling up with 93 octane to see if it goes away