WAS DRIVING AND HIT A BUMP, THEN ONLY ON HEAVY ACCELERATION THE ENGINE NOISE WAS MUCH LOUDER. BEING UNDER WARRANTY I TOOK IT IN FOR SERVICE. THEY SAID THEY CHECKED IT OUT, PUT IT ON THE RACK, DID A DIAGNOSTIC CHECK AND FOUND NOTHING WRONG. THEY EVEN SAID THE MECHANIC DROVE ANOTHER HHR AND THAT IT SOUNDED THE SAME, THAT THEY ALL GET LOUDER AFTER BREAK IN. WELL THE WHOLE STORY SOUNDED A LITTLE FISHY TO ME. DURING MY NEXT WEEKLY ENGINE COMPARTMENT CHECK, I THOUGHT I WOULD LOOK AROUND. I WAS LEANING OVER TO LOOK AT THE EXHAUST HEADER, AND I BUMPED AGAINST SOMETHING LOOSE, I BACKED UP AND FOUND THE AIR CLEANER HOSE HANGING LOOSE FROM THE AIR CLEANER. SO I PUT IT BACK ON AND TOOK IT FOR A TEST DRIVE AND ,, LIKE ,, GEE WIZ,, THE ENGINE SOUNDED NORMAL AGAIN. NEEDLESS TO SAY IF IT WERE A SNAKE THEY WOULD HAVE GOT BITTEN,, AND LET THE SERVICE DEPT. KNOW ABOUT IT, WITH A LITTLE NAME CALLING

 

Well, it was a simple fix...too bad your dealer didn't look closer..
But it is kinda getting that way in some dealerships..

 

There's no diagnostic code for simple mechanical problems. A Dodge dealership insisted there was nothing wrong with my Ram since there were no codes set, even though it ran like poo and pinged due to a leaking manifold gasket. Had to fix it myself eventually.