2003 TT w/auto trans (daughter's car)

She reported it's running rough & had a CEL. Checked codes - got 300, 301, 302, 303. All cyls but four are misfiring. I searched elsewhere in the forums, found a couple threads on this, did the following:

- replaced plugs (even though they're only a year old)
- did not replace coils as they were all replaced < a year ago (one only 2 months back) - but I _did_ swap coils on cyls 1 &4
- replaced o-rings on all injectors (looked like a couple were leaking at the intake manifold end)
- ran 1/3 pint of Seafoam injector cleaner through a vacuum line (as recommended elsewhere here), which produced a lot of white smoke but seems to have helped.
- Changed air and fuel filters

Now I have the following codes:
- 304 (cyl 4 misfire) and 113 (intake air temp reading too high)

And the trans has started acting up - went several miles in 1st gear w/o shifting when dughter was driving it. I took it for a test drive, it seemed to upshift OK, but downshifting was harsh - a big "thump" as it slammed ito a lower gear. I know rom experience that this will wreck the clutch pack, so need to fix it quick.

I don't believe in coincidence, but I'm stumped as to how a tune-up can cause transmission troubles - any suggestions?

And is it really possible that I've got yet another bad coil?

 

Coil packs sometimes feel like a crap shoot. If you swapped packs and the code follows the coil pack, the you have your answer. However, if the misfires stays, the problem can be in the coil pack harness. This is also a common problem on older cars. Dint know how to help on the trans, just know that the tips suck.

 

So you swapped #1 & #4 coils now a cylinder that was not previously misfiring is misfiring now?

Is it a hard misfire!

Were factory coils installed or Chinese crap from Autozone?

 

Not sure if it's a "hard misfire" - how do I tell? I Just get the one code, and the motor runs a bit rough.
I suppose the coils I've put in are indeed "Chinese crap from Autozone". Are you saying I have to replace them all with "genuine Audi" parts, or can I try somewhere else? Cost is a factor for me.

 

How much does it cost to keep replacing inferior products over & over again!

Make sure they are either Audi or BERU coils. Also make sure the correct spark plugs are installed (not champion , autolite or AC Delco) preferably again OEM.

I am very frank on my beliefs because i do this for a living , have bitten in the *** more than once trying to save a customer money & in the long run it ends up costing me!

One more thing. Check the wiring going too the coils & make sure there are not any bad connections. Disconnect #4 coil while the engine is running & see if anything changes. If no change , the coil is most likely junk , stick a fork in it , go with oem or keep riding the merry go round!

 

The coil pack should have some sort of warranty and if it is bad, should be replaced. Still don't know if the misfire moved with the coil pack or stayed with the cylinder.

 

M5S5 - any suggestions on where to get coils? Nearrest Audi dealer is 100 miles away, so i pretty much have to mail order. Who has "good" coils?

 

to help save money on coil,: tip, i checked out autozone.com and a lot of dif places to find a good price on a coil,.. dealer ship was the most costly... i went with dealer ship brand, looked it up on ebay, and scored it for over half the price

 

Again - I don't have a dealer anywhere near me. WHAT BRAND is considered acceptable? WHERE can I get them? I'm using "chinese crap from autozone" because I don't have a clue as to reputable/good suppliers or brands - and AZ is the only thinkg available to me around here.

 

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