[ramspeed]

I'll give you all a run-down of the past two weeks or so.

Driving around, about two weeks ago, punch it hard, car goes into limp mode.
Take it to pepboys(to diagnose code) but when I turn the car back on, limp mode is gone.

I bought some Seafoam fuel additive, put it in the gas. Everything went fine.

This sunday, I start the car, its running really rough, sounds like it might be misfiring, but no codes show up. Let the engine warm up, rough sound goes away.

Same thing, this whole week.

Then today (Friday) I start the car this morning, and its running more rough than the past couple of days, service engine light comes on, and I have to keep the car at 1000 rpm or higher for fear of stalling.

Start driving to the dealership, after about 5 minutes, car runs like a champ. SESL doesn't go away, so I scan it. Get these codes:

P0301
P0300
P0104

Take it to the stealership, they charge me $140 to say the same thing, and tell me that it might need to have its ECU reflashed, or reset, or whatever.

What is going on?

Like I said, when the car sits for a little while, it runs REALLY hard on startup, but when I drive around for a bit, it seems all better



NOTE: only modifications are dual cone intake, and I unplugged the exhaust diaphragm actuator (to make the exhaust louder on a 335i) I plugged it back in this morning.

[CHECKERED]

Miles on the car?

How many miles on spark plugs?

Carbon cleaning ever been done?

Which intake do you have? Some brands position the MAF sensor too low causing all kinds of shenanigans

[joec500]

leaking injector causing a super rich startup condition. Find out which cylinders are mis-firing, replace those injectors. They can be found for 100-150 online for new ones + 8-10 dollars for decoupling units. Then find someone who can help you to code them. There is a great DIY somewhere on the forums.

[ramspeed]

Awesome, thanks for the advice, it's never had a carbon cleaning or anything I don't think. It's got about 67k on it. I will try getting the dealer to replace the injectors, isn't there a factory recall or something? Maybe it is the coil pack(s)

[ramspeed]

Originally Posted by joec500

leaking injector causing a super rich startup condition. Find out which cylinders are mis-firing, replace those injectors. They can be found for 100-150 online for new ones + 8-10 dollars for decoupling units. Then find someone who can help you to code them. There is a great DIY somewhere on the forums.

So if I see that cylinders 1 and 3 are misfiring, is it safe to assume that those are the injectors I need to replace? Also, could it be the coil packs?

[CHECKERED]

Before replacing try swapping coils or injectors to a different cylinder and see if the problem moves to that cylinder