So my 2005 A4 1.8T had a very rough idle and flashing CEL, I then researched and ordered new spark plugs and coil packs and installed them into the car, and no luck.

I then took it into the a shop and they changed the Crank Case vent Valve and the sort of fixed it as the idle was MUCH smoother, however the CEL did come back on (not flashing).

I can smell fuel, i hear some misfiring and am confused and tired of searching all over the internet!

I do remember that RIGHT before this happened I filled up at the local corner store with gas (crap i think now) and 10 mins later I was experiencing a rough shaking car!

Now Im going to put STP in the car and CLEAN Chevron or SHELL and flush it through once before taking any further action.

The mech. i took it into said that 8/10 of the codes were eliminated, and so was the rough idle, however expect that not all are. He said he would give me an hour of free diag/labor since it came back.

My options are:

Take it to Audi and become homeless $$$
Go back to the shop and have them poke at it but get an hour of labor free (just dont want to come back to a bill of $$$$$$$$$ for **** that doesnt work)
Take it to my folks place 35 miles away (our neighbor is a mech) and he can look at it (honest opinion included)


I hear it could be

MAF
VAC leak
Fuel Filter
Fuel Pump

What do you guys think? Ideas? Personal Experience?

Thanks for your time and help,

Much appreciated my friends.

 

You should be able to do the

MAF
VAC leak
Fuel Filter
Fuel Pump

If you have a driveway and a jack with some tools. Not super hard but it's best to narrow down the possibilities. Once this is done do the work yourself if you can. Also, post the scan codes you're getting.

 

So now I have had the coil packs changed, spark plugs, crankcase vent valve and some of the breather pipes (made outta plastic) replaced. I used to have 10 codes, now I am down to p0171 and p0507 and a check engine light. So far there has been much progression and now I am on the last step.

My mechanic is suggesting changing the o2 sensor.

Ideas?

 

GOOGLE THOSE 2 CODES AND SEE WHAT COMES UP. Usually when you enter codes in Google, the results you get will come with a cause and possible solution. Google is your friend.

 

Heck, just out of curiosity, I googled the first code and found something ON THIS VERY FORUM that has some info on BOTH codes.

https://www.audiforums.com/forum/sho...d.php?t=146775

 

intake breather valve. The way to test. is with the car running........ if you can't or it is very hard to removed the oil fill cap, you have a faulty breather causing too much internal vacuum.