View Full Version : misfiring problems with codes p0140 and p0302

03-04-2014, 10:04 PM
I have a a4 atw 1.8t. so recently my car has been sputtering while accelerating. about a 2 weeks ago it was bad enough where it misfired and threw these too codes p0140 and p0302. I put in a new forge 007 dv and replace the front 02 sensor i was going to replace the rear but from what I've read its only jobs is to see how the catalytic converter is doing. i was thinking that it may catalytic converter not working. could that cause misfiring or not have a good rear 02 sensor cause this. I'm planing on put in a test pipe in a few days as well as change the spark plug. and help would be great I'm stumped on this one

06-10-2014, 01:24 PM
I am having the same exact problem, only my car threw the P0140 and P0304 misfire on cylinder 4. Did you find a fix and when you where having this problem would your car go into limp and trip the epc light and cut throttle response?

06-10-2014, 10:21 PM
so i found out what i think is the problem when i installed a boost gauge. i saw i was making more psi then a stock car should so i took it to a shop and found out that the car already had a tune, but i never knew that when i did the spark plug so i had the wrong gap which is why it would go into limp mode. it was working fine but my misfire in cylinder 4 came back recently I'm thinking its the coil pack now i just switch it to cylinder 1 to see if the misfire moves with it or it could be the wiring to the coil pack since it wears down from the heat coming from the engine. ill keep you updated when i find out more