Cylinder 3 Misfire

vBlxrrr

vBlxrrr

Greenie N00B Member
A few days ago the car threw the code P0303 which is for cylinder 3 misfire, I put a new plug in the car and it kept misfiring (Yes it was gapped correctly). Swapped coil packs and even used one off of an MS6 and still the misfire was there. I did a leakdown test on the car and it was good, compression test came out fine as well. My AP says that my IPW (Injector Pulse Width) was about 0.67 at idle and my HPFP Pressure was all over the place between 75-190 while idling. Driving is fine, but if go wide open throttle it will start backfiring pretty bad. Im not getting anything for Knock Retard (other than the normal random knock here and there that probably isnt even knock). Im just lost, could it be the injector for cylinder 3?
 
Check the wiring harness to the coil and stretch the spring inside the coil
 
You were probably misfiring from running lean. The typical idle pressure is around 400-500psi so you're low.

Make sure that you're getting 60 psi fuel pressure when your engine is cold so that'll show if your ITFP is working correctly. Go KOEO (key on engine on) but don't start to check that.

Another issue can be your PRV. After your engine is up to operating temperature, turn off the car and go back to KOEO and watch fuel pressure. If it keeps rising while the engine is off then your PRV is good. If it starts dropping off quickly then you know it's bad.

Those are the two basic/easy things to check to start off. Also if you have any logs feel free to post them.
 
vBlxrrr said:
A few days ago the car threw the code P0303 which is for cylinder 3 misfire, I put a new plug in the car and it kept misfiring (Yes it was gapped correctly). Swapped coil packs and even used one off of an MS6 and still the misfire was there. I did a leakdown test on the car and it was good, compression test came out fine as well. My AP says that my IPW (Injector Pulse Width) was about 0.67 at idle and my HPFP Pressure was all over the place between 75-190 while idling. Driving is fine, but if go wide open throttle it will start backfiring pretty bad. Im not getting anything for Knock Retard (other than the normal random knock here and there that probably isnt even knock). Im just lost, could it be the injector for cylinder 3?
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Sounds like your pressure relief valve. It's a common issue and it gave me a cyl 3 misfire.
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