Ever since I installed a helix catless down pipe, my car has been back firing quite frequently. On another note I caused my car to misfire cylinder #3 launching it too hard somehow. This was when my only mod was a leaking helix up-pipe, 3/16th mod, and snorkel delete. I had to drive the car in limp mode to a mechanic.

 

i think this is what im getting cause i see flames... and poping towards the muffler end...

edgar,

 

crank pulleys can cause a misfire code due to their smaller mass decreasing the rotational inertia of the crankshaft. note that in this case an actual misfire is NOT occuring, but rather the ECU thinks that one is. this is due to the way the ECU determines misfire in the first place, which is the pickup of minute differences in the rotational velocity of the crankshaft as each cylinder fires. some users report lots of misfire codes with a lighter pulley. as expected, some users also report misfire codes with a lighter flywheel, since it decreases rotational inertia as well.

there are also stories of "cursed" cars that cannot shake the misfire code no matter what is tried... reflash, new coils, new plugs, new crank/cam sensors, etc.

hth
ken

 

"there are also stories of "cursed" cars that cannot shake the misfire code no matter what is tried... reflash, new coils, new plugs, new crank/cam sensors, etc."

If this is the case would it be a cracked piston or warned rings? I'm having the same problem.

 

it COULD be a cause. a compression check would give you the answer to that. in many of the aforementioned cases, compression tested out fine. there was no apparent reason for the continual misfire codes.

hth
ken

 

Ken,

Have you ever had that problem? I only have 18k miles and removed my lighten crank pulley but still getting a misfire code. I will try and replace the plugs to see if it resolves the problem. If this doesn't work I will get a compression test.