Engine Sputtering and car shaking

tmporter · Post by **tmporter** » 02 Jan 2011, 15:35

My 2002 S80 has recently encountered a problem where the engine sputters when the accelerator is pressed and the entire car shakes at the smae time. If the car is driving without accelerating everything appears to be beeter but not perfect. My check engine light will flash on and off while driving and stay constantly on when idle. I have changed the spark plugs and fuel filter to no avail. Auto Zone hooked their tester up and said I had a bad tank of gas. We added fuel injector cleaner and it still hasn't worked. Does anyone have any suggestions?

Post by **boosted5cyl** » 03 Jan 2011, 10:33

CEL Flash = misfire, most likely a coil or two. re=check all the connections. Get the codes pulled and write all of them down. Myabe try another autozone because theres no real way to tell about "bad gas" from an OBD code reader. I know you said you replaced the plugs, the plug type and gap is very important on the T6. If unsure you can throw a set of basic copper plugs in and gap to .028". You HAVE to correctly gap the plugs with this motor.

My money is on a coil issue. You can check to see which cylinders are misfiring yourself....

Have the engine idling and disconect injector power connector for each cylinder for about 5-10 secs, then replace it. If there is no change in the sound of the engine when you disconnect it then that cylinder is dead. If it dips or stalls, then that is the cylinder at fault. It may be more than one cylinder of course. When you find the cylinder that is misfiring swap the coil in that cylinder with a known good one. So if it appears that #4 is misfiring, swap the coil with #1 and re-do the test above. If the misfire moves to that cylinder, then the coil needs to be replaced. If not, you have more work to do. in this case it could be a loss of compression or a clogged\defective injector. Again though, most likely its a coil.

Drive the car as little as possible. If it is an ignition issue it will be passing raw fuel into the cat which is not good for its health. If you narrow it down to a coil, but cant afford a replacement right now and need to drive it, leave the injector disconnected for that cylinder.

Post by **boosted5cyl** » 04 Jan 2011, 10:55

Ironically I started getting a misfire yesterday after posting this. Isolated it down to cyl #4, swapped the coil with #1, misfire moved to that cylinder. Picking up a new coil from Oreillys today