Misfire like symptoms

MBRUVERIS12

MEMBER
2007 AUDI A4
2.0L
4 CYL
TURBO
4WD
AUTOMATIC
150,000 MILES

My car, when accelerating from low RPM's seems to misfire at certain times. The check engine light does not flash or come on. I have changed the spark plugs and the coils and the problem is still there. It seems to happen most in low RPM and low speeds. If I give more gas, past 3,000 RPM's the problem never occurs. Only from 1500-2800 RPM's do I get this misfire like problem that happens. Not sure what could be causing it, hopefully you can help me out.

Friday, September 27th, 2019 AT 8:21 PM

2 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Hi,

More than likely you have a fuel issue. You have a low pressure fuel pump and a high pressure fuel pump. I suspect that you either have a fuel delivery issue on the low side or the high side pump isn't producing enough pressure until the RPM's get higher.

Is this vehicle all stock or have you done any alterations to the turbo or computer?

We need to start with fuel pressure readings but you need the low side and high side. So if you don't have a gauge for high pressure systems, then we will need to visit a shop that can inspect that.

Also, you can try unplugging the MAF sensor to see if that changes anything. If the MAF is not reading the incoming air properly then it will not send the proper amount of fuel.

However, this is just a guess at this point because we don't have anything more to go on other than it sounds like a fuel starvation issue.

Let me know and we can go from there. Thanks

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Sunday, September 29th, 2019 AT 8:52 AM

MANOS DOUKAS

MEMBER
2 POSTS

I have the same exact problem (but I have upgraded the software stage 1 from 180 hp to 260 hp ) I have a petrol 2.0 tfsi audi a6 c7 ae888 model. I changed the intake manifold (after error 2015 and 2004) but the problem persists.

I have also to add that after the car has reached operating temperature the problem becomes less.

I should say that I dont know if it is misfiring more to me it seems that it is weak, shakes and overall I feel it loses its linear increase in power and smoothness in the ride. After 3000 rpm it becomes "crazy" revving up very quickly.

Thank you

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Sunday, October 2nd, 2022 AT 2:24 AM