About a month ago my car started misfiring only at cylinder 1 (p0301). I changed the ignition coil and it fixed the problem instantly. 2 weeks later the problem is back. the ignition coil was still under warranty so I exchanged for a new one. This time it did not fix the problem. I also tried changing the spark plug twice and the problem still exists. I've been driving my car with this problem because it is currently my only transportation to work. When idling in park or neutral if I apply slight pressure to the gas pedal the misfiring goes away. If I apply anymore measure or any pressure at all under load (in drive or reverse) the car misfires. On the highway if I put my car in cruise control I could feel the misfire quickly but randomly come and go. I don't know what else to do. I'm getting terrible gas mileage and my car smokes after hard throttle. Too scared to try wot. Btw also when I took the spark plug out it had a little oil on it. Any help would be greatly appreciated. Please no trolls. Thanks in advance!

 

No year, no model, no help

Search for the FSM

Telcoman

 

Sorry.
2003 G35 Coupe 5at
I alteady have the fsm.

 

So have you followed the troubleshooting steps?

http://www.nicoclub.com/FSM/G35/Coupe/2003/ec.pdf

See page EC-290, EC-291

Diagnostic Procedure
ABS003CO
1.
CHECK FOR INTAKE AIR LEAK AND PCV HOSE
1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leak.
3. Check PCV hose connection.
OK or NG
OK >> GO TO 2.
NG >> Discover air leak location and repair.
2.
CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace it

Telcoman

 

My pcv hose is cracked at the end connecting to the plenum, I'm going to order another. should I also replace the pcv valve? Could I use electrical tape as a temporary fix?

 

Update:

Went and got another diagnostic scan after changing my #1 coil with a new one and then swapping the #3 and #1 coil. That puts the new coil at #3. Th scan read:
P0305 Cylinder 5 Misfire Detected
P0550 Power Steering Pressure Sensor Circuit
P0011 Intake Valve Timing Control Performance
I swapped the #5 coil with a used one I forgot I had and reset the ecu with the gas pedal procedure and wallah no more codes. I know the power steering code will comeback up but that'll be getting repaired very soon. Thanks Telcoman.

 

NP

Glad I was able to put you on the right track to find the root cause

Telcoman