02 A4 1.8t 5speed with APR Tune 93 Octane, APR Stainless Exhaust And Carbonio Intake Low Power
Not really sure what HP the car should be putting out with all the mods but I don't think its even getting full Stock HP. It doesn't appear to be holding boost however I do hear the DV when I release the throttle. It has 107000 on it and I had the water pump, timing belt, belt tensioner, Hoses, Cam tensioner Seal and valve cover replaced because I had no service records with the car. All this work was done at an Audi Shop here in Charleston. I have personally change the plugs, Fuel filter and clean the air filter to try and resolve this issue. I'm pretty certain there are no vacuum leaks but Not sure of boost leaks. Going to check that in the morning. Please help its my first Audi and I'm growing sick with all the money it cost me in the first month of ownership.

 

Well I did find a boost leak, repaired the issue and it does appear to be a little better. However, now I'm getting a miss fire at about 3500rpms in first. Idles smooth and runs out smooth at normal throttle. Any thoughts Anyone, Bueller, Bueller???????????

 

The following comes with the disclaimer that I am far from an expert - I'm just using some basic logic along with what I've read on the internet over the last few years of owning my A4. Hopefully someone with more expertise will come along soon to do more than speculate, although they'll probably want you to get the car scanned for codes in order to assist in the diagnosis.

I'm assuming based on the lack of boost figures in your posts that you don't have a gauge or VAG-com to log with? My (mostly uneducated) guess is that the leak you fixed wasn't the only one, and that you're still losing metered air somewhere and thus running rich. A small leak wouldn't be noticeable under low load (vacuum or low boost) because the variance from the MAF sensor's reading would be small, but as soon as you put your foot down, at the onset of high boost levels (3500 RPM sounds pretty close to right for the stock turbo with a tune), you'd be pushing quite a bit of metered air out of any leaks, thus running rich until the O2 sensor readings cause the ECU to compensate. This *could* manifest as a stumble/misfire.

Again, I am not an expert, and am posting as much to see what the real experts say is wrong with my theory as for any other reason. I do know that scanning the car for any codes which may be present (and probably clearing them, driving for a while, and scanning it again) would definitely help you with your diagnosis. Of course, you could always do the truly crazy thing and take it back to the shop that put the APR software on there and see what they can do for you.

 

Thank you for the advice, I pretty certain there are no more boost leaks. I use this method here :: a4mods.com :: - The Premiere Audi A4 Modification Guide and Pictures Library to test for leaks. As far as taking it to the shop who installed all the APR mods, I wish I knew. I bought this car with all the mods already in place. I did however have my shop verify that the 93 octane tune was still there. I would just take it back to them but I paid $7,000 for the car on 12/15 and just spent $1238 Wednesday for the other work I mentioned. All out of cash for the car at this point plus the more I know about it the better off I'll be down the road.

I've been reading just about every thread I can find with what sounds similar to my issues and going through everyone's suggestions.

Thanks Again!!!!!!

 

Well, another possibility is that you could have a coil pack that's dying, or one of the spark plugs' gaps could be off from where it should be. Did you measure the gaps when you put them in?

 

It could be the coil packs.... Had a misfire around the 3k range then the coil packs for cylinders 2&4 died. Got the most updated ones and she's great

 

Thank you guys for the advice, I'd did order new coils today and also found the 2 of the coil connectors on the wiring harness were dried up and busted. So I am replacing them as well. I'll keep you posted on the results after the parts get here tomorrow.

 

I have an 03 1.8t 5 speed avant APR stage 1+, APR stealth exhaust. I have been telling my mechanic, (Who thankfully is a good friend) that I have noticed loss of power much like you are describing. My wife even noticed it,... Weird. I live in the mountains and it was most noticeable going up the pass. My friends c4 s6 has been crushing me to the trail head. I had him replace the clutch with a single mass clutch and the power has returned. I knew it was on the way out but he said it was cooked. Just wondering how your clutch feels? Mine was engaging super high on the pedal.

Not sure if this is helpful but singing the Audi blues is not fun.