2003 Audi A4 hesitates at highway speeds and not at idle

audi
a4

#1

Hello,

My wife’s 2003 A4 1.8T Quattro has 99000 miles on it. One year ago, New Year’s Days in fact right after my Saab 9-5 had a fuel pump die, I lost two coil packs on the way to get the Saab. Those were replaced and the car has been generally reliable since. Recently however, over the last month, we have noticed a hesitation/misfire at highway speeds and in the last week, increasing frequency, particularly after the engine is warm and can happen at idle where the car sounds as if it were about to stall.

I have a ScanGuageII hooked into the OBD and it detected nothing. Voltage is good 13.7-14.1 even during sputtering. I took it to an import mechanic who noticed a misfire on #3’s history. We moved the coil pack to #2 and drove it, missed, and rescanned. Now it was #4 complaining…I do not think it is a coilpack. Plugs look normal.

I have been reading online about a possible 2003 A4 1.8T fuel pump recall and it makes sense with intermittent failures that are similar to a misfire. I believe the fuel filter was replaced about two years ago which would be in the neighborhood of 20000 miles or so by an Audi mechanic. I have run through two tanks of fuel, from differenet suppliers since this issue has taken root and each tank had a product, one for removing water from the gas and another for fuel injector cleaner to no avail.



It’s my wife’s car, it’s cold and it’s Wisconsin. Please help.



Thanks much,



Carl (husband to a native Californian)


#2

That should read, and NOW at idle…


#3

Did you get the coils from the dealer? After market coils are all junk! and there is a recall on the coils now…I could be a partially melted cat…When the coils fail, the injector is still going, fuel inters the 2000F cat and makes it 3000F+…
The wires/connectors going to the coils also fail, get brittle, crack and short out…
I work on lots of Audi’s…and drive an A4 with a 1.8T…
The breather system is hokie also, all the hoses from the valve cover to the crank case get mushy and develop holes.


#4

“only quality ignition coils from the car maker.”? But, the car maker INSTALLED the ignition coils which are under RECALL, now?
A fuel control problem would affect ALL cylinders, not just #3, or #4. I would follow a troubleshooting chart, such as one from alldata.com.