: Deal or no deal?

01-19-10, 11:57 AM
hey everyone,

I recently brought my 2003 SLS into the dealership due to the car idling rough, and jumpy. They said it is miss-firing and i need to replace the plugs and wires. They also want to replace the air flow sensor harness.

So, they want $330 for parts and labor. Is this a decent price? Thanks for all the help. Please move if this is in the wrong forum.

01-19-10, 02:13 PM
There are no spark plug wires on a 2003 Northstar. It's a COP (Coil On Plug) ignition system. You remove the coil cassette on each cylinder bank, pull the spark plug boots, and change the plugs. A GM dealer would know that.

MAF harness (5 pin connector) might be due to a broken wire, but I have no idea where the harness terminates or connects to another harness - the MAF signal goes several places at once, so the "harness replacement" thing is a stretch........check the intake duct from the air filter side to the throttlebody - there are 3 clamps plus the intake quieting resonator, all of which, if loose, will play hob with idle and acceleration. (In the intake duct picture, the resonator has been removed and replaced by a 2" rubber pipe cap - any hardware store.)

$330 is about right for a 2000+ Northstar plug change. A GM dealer will make their money on parts markup plus about 2 hours labor.

EDIT: How many miles on this car ???

01-19-10, 04:05 PM
Have the crankshaft position sensors or the intake plenum ever been replaced? Those are common problems on your era N* that could cause those symptoms? Check for codes.