im new to this but i have a similar problem. mine is 2004 ls v8 3.9. I GASSED IT ONE DAY AND MY CHECK ENGINE LIGHT CAME ON. THE COMMOM LS PROBLEM!!! COP IS PROBABLY OUT! I COULD FEEL IT WHEN IT WAS QUIET AND IN IDLE, BUT NO BIG POWER LOSS/ DIFFERENCE, 1 WEEK PASSED APPROX AND I CHECKED THE OBD CODES i had a missfire, erased the code (FORGOT THE STUPID CODE NOW I DONT KNOW WHICH CYLINDER ITWAS IN!) , NOW 3 WEEKS PASSED I CAN FEEL LESS POWER ANDMY GAS MILEAGE GONE SOUTH, ITS AT THE DEALER RIGHT NOWCUZ MY POWER STEERING PUMP WENT OUT. MENTIONED THE MISFIRE( HE WROTEI SAID MY CHECK ENGINELIGHT WAS ON BULL:q:q:q:q !) I TOLDHIM THE LIGHT CAME ON I ERASED IT AND SO ON. I CALLED THE GUY TODAY. HE SAYS NOTHING AT ALL IS WRONG WITH THE CAR ONLY THE STEERING PUMP. I KNOW THIS IS NOT THE CASE WHEN MY CAR IS GETTING 14 MPG CITY WHEN I RESET THE FUEL METER BUTTON ON MY DASH, AND THIS IS GOING 30 MILES PER HOUR ON A LONG STRETCGH FOR5 MIN , NO BRAKING NO GASSING, ETC. SO I KNOW THIS GUY PROBABLY DIDNT EVEN ELECTRICALLY TESTS THE COPS'. DOES ANYONE KNOW A RELIABLE PLACE IN LOS ANGELES WHO ACCEPT WARRANTIES TO GET THIS TAKEN CARE OF BECAUSE IM AM SO SICK OF THESE DEALERSHIPS.
IM STILL PROBABLY GOING TO GET CHARGED A 100 DLR FEE JUST FOR DIAGNOSTICSTO TELL ME THERES NOTHING WRONG WITH IT BECAUSE I SAW THE CODE ITSELF AND I ERASED IT.
ALSO ANYONE KNOW OF A WAY TO TEST MY COP'S WITH A TESTER, DEVICE, RENTAL DEVICE, AUTOZONE ETC, I NEED HELP.
