griffin14

i just bought a 1999(b5) audi a4 1.8t quattro sedan automatic, i needed a vehicle in the cold canadian winter to get into the base for work since i cant take the bus anymore, the audi seemed like the ideal car. when i went to check the audi out the only problem seemed to be an exhaust leak, but it rand fine when i test drove it, it has 220,000km and i got it for $2,200. ive had it for about a week, and somedays it drives fairly decent with only minor issues sometimes, but randomly when i go to stop it almost wants to turn off, and it will sputter then go back to sitting around 800rpm while im sitting there, it will than accelerate fine after stopping most of the time, but theres been incidents where it will barely move and just sputter while trying to get going and the rpms will bounce between 500rpm and 1200 or so and i can barely get any power and only hit about 10km an hour and at some point it will just get power again and drive normal, this problem also happens once in awhile if i punch it around 4500rpm, it will lose power for a bit and than go, its not turbo lag, its just not getting any power at ll and bogs out, i was running 87 octane and will be switching to 91, i was thinking possibly it can be a boost or vacuum leak, or possibly the air intake is filthy and not breathing and getting enough air, or with the exhaust leak its not getting enough back pressure sometimes, im far from a mechanic but these were just thoughts about the issue, if someone could help me out on what it probably is and where the issue is and how to fix it and the price and if its easy enough to do by myself that would be great. i also hear humming from the rear once i hit about 60, i assume that its a wheel bearing and how much that would be. i also need a new control arm, but its not bad at all, and when my car shifts sometimes it will randomly jump up from 2400rpm to 2800 than shift, also my triptronic wont work, so that would be the transmisson issue but i have no clue how to fix or what exactly is causing it. also I do smell a burning smell once in awhile if I stand outside, it needs an oil change but there is still oil in the car, and the gas pedal has a lot of play before I accelerate and the car seems surprisingly slow. sorry for the long thread, would just like to get this car running decent, as i moved out of my parents and cant take a bus to work since my house is in the country and the military base is in the city

twentysevenlitres

You really need to scan it with VCDS to determine any faults.
The idle and stuttering problems sound possibly like the engine speed sensor. That should show as a fault, or may show in different ways such as 'multiple misfire'. Do you have any problems starting it? As the ECU uses the engine speed sensor to close the after start relay (keeps fuel pumping).
Otherwise a boost leak would explain low power and intermittent issues due to overfueling. Any black smoke? You could pull a spark and see if it's black (healthy colour is a light tan/grey).
Vac leaks also possible, you should be able to hear those as a slight hissing noise in the vicinity. Should cause almost constant poor idle though!

Rear wheel bearing is not really a DIY job, as the bearing is pressed into the hub carrier. You need a hydraulic press to remove the old and reinstall the new bearing. The bearing itself is only $30 to $50 depending on quality (highly recommend SKF or Koyo here), and you could save a few $$ removing the hub carrier and taking to a mechanic or bearing place, as it's a fiddly job that's not all that difficult (perhaps not for a first timer though!). Make sure you get a Quattro bearing.

griffin14

I appreciate the help, it's helps alot!! it doesn't have any problems starting nor does it have black smoke puffing out

jseklund

Pop the hood and look around for any hoses, etc. that aren't connected or may have rotted. You may find something that is obviously disconnected.

A VCDS, as stated above, would be another great first step.

Beyond that, we are guessing....

griffin14

I'd gotten a friend who's a mechanic at a shop by my house to book a place for my car to go in, he said they'll scan it but he mentioned the same things you said, thanks!