Thread: 3.8 hesitating while accelerating!!!

I have a 2000 Pontiac Grand Prix GT I picked up recently for $500, the car is in great shape with 110,000 miles on it. The car was running amazing till yesterday. As I was accelerating I could feel what felt like a hesitation or misfire, once you let off the gas the car cruzes great again no codes were coming up at this time. I plugged my computed in once the service engine soon light came on, the computer came back with a P0306 and P0306PD. If I am correct that's a CYL 6 misfire. What would be the main culprit of this? I was planning on starting with the easiest first, plug, wire then coil pack before I start doing anything with the injector or cats. I know with some of the other vehicles I have worked on that have a similar problem the coil pack was almost always the culprit. I have a large amount of mechanical knowledge and an auto shop worth of tools, however I have never owned a GM car before and know absolutely nothing about them besides that the 3.8L is a solid motor. From what I have read this problem is caused by everything from a bad spark plug to a clogged cat or bad fuel system on these cars. Also side note, the problem is getting more noticeable, the car still cruzes great at a consistent speed but is jerkey while accelerating, the same code is still appearing.

That's what I was planning on before I purchased one. I have no clue when the plugs were last changed so I need to do those regardless. Forgot to add, I had a spare mass airflow sensor laying around so I swapped that out. I've heard that can be a cause of this problem but it did nothing.

Typically if a coil fails you'll get two cylinders misfiring, since one coil fires two cylinders.

The ignition control module seems to also be an issue with these engines. Luckily those can be tested. It resides under the coil packs.

If you suspect a coil pack you can try swapping them to see if the misfire follows where the offending coil gotest to help rule out any possible mechanical issues with the engine.

I didn't think about the ICM, I'll test that later.

Yep it was the wire.