So I bought my S4 on April 19th. Its a 2006 with the 4.2l V8 and 6 speed manual with about 104,000 on the odometor Drove it about two hours home, perfectly fine. Drove it to and from work with no problems what so ever for the next few days. Now the fun part... Wednesday night (the 23rd), I went to get food for the gf. On my way back, I got about two miles from home, went to make a left turn, and my car felt like it was running on one cylinder... Pulled over to the side and shut it off. Gave it a few minutes, ran the pocket scanner on it (no codes at the time), started it back up and tried to drive off. Everytime I put it in gear, I could floor the gas pedal and go slower than a snail. I ended up finally getting a code, even though the check engine light never came on. P2234 (bank 1 sensor 1 O2 sensor). Ok. Got the car towed home, next day went and got the O2 OEM replacement. Switched it out when I got home. No dice.... In fact, it was worse. Tried taking it for a drive, and had serious power loss still, as well as now I was having multiple misfires and the check engine light flashing on and off at me. Put it back in the garage. Then I proceed to change out the spark plugs. I replaced them with NGK BKR6EIX. Still did not solve the problem. So I gave up for the night. Next day (its friday now), I couldn't do anything except find some spark plugs that matched what I took out of the engine (BKR6EQA) and had to wait until the next day to pick them up since I got off work late.

Now it's Saturday. I start taking everything off the motor I can get to. After doing some research, I found a couple different things it could have been. Possibly the plastic intake flap (nope. wasn't seized. moved perfectly fine.), cam chain tensioners (nope. chain was nice and tight, nothing broken or missing). I even changed out the other O2 sensor with a new OEM replacement, and replaced the spark plugs again. Started the car up, ran for about a second, and died. And it does that everytime it starts. Sometimes it doesn't start at all. So I did some research again and scanning for codes. This time I got a p0113 (IAT sensor failure). So I try running the car with the MAF unplugged.. no dice yet still. Research said it could also be the fuel filter. And of course I have the special fuel filter that noone has in stock except ordering it online. So that I will have in the mail tomorrow.

What other parts could it possibly be that I may be overlooking? I've changed just about everything I could think of without replacing the whole damn motor. I'm starting to get rather annoyed with this.

One other thing I'm thinking of is possibly the fuel pump. I didn't have any problems with it until it got to a quarter of a tank left. I've only had the car a week and it came with a full tank of gas. I haven't stopped to fill up a travel gas tank yet cause I keep forgetting.

Please help with any ideas or solutions that you've come up with for a problem like mine.

And I'm not sure if its relevant or not, but I also can't get my VCDS-lite to connect to the ECU. I can scan the radio and some of the creature features, but not to the computer. Any ideas if that might be a symptom? I can still get my pocket scanner to read it, but thats only good for generic codes and such.

 

Sounds like something in the timing system. Broken tensioner, broken adjuster, broken tensioner guide... I found a great read up that might help! B6/B7 S4 Timing Chain FAQ / Information / Discussion Thread

 

Hopefully not that^...

I had a similar problem a couple months ago. What happened was a piece of plastic, about 1x2 inches, unattached itself from the back of the MAF, and got lodged into the throttle body, so it was always open a little, but couldn't open much more. Really threw off the air/ fuel ratio which caused it to run super shitty, no power, etc. Chances are, that is probably not your problem, but it's worth peaking in there just to make sure.

 

I took the throttle body off and cleaned it when I took the intake manifold off to inspect the plastic flap. And the cat clogging does sound like a little bit of a reach, but it might be the excuse I could use to redo the exhaust anyways. The mutiple misfires didn't happen on one side though. It was about 6 of the cylinders, I think 3 on each side

 

So, I feel like a bit of a dummy today... last night I had a bit of a revelation. Since I had only had the car a week, I sat for a little bit and thought about how much gas I should have used. Then it hit me.. I'm probably just out of gas even though my gas gauge says I have a quarter tank left. So, I get a 5 gallon gas can and fill it up, put it in the car, then after a few cranks to get fuel back in the lines, it starts up with absolutely NO problems at all. Holy crap.... I'm a little embarrassed about this one..

So now the hunt is on for a new fuel level sender and see if that's my issue, or if it's something in the wiring up to the gauge itself. Good news is, is that I now have some really crappy plugs out of the car and new ones in it, and some other maintenance stuff done that was needed.

 

I think I would have missed that too, considering it still had a 1/4 on the gauge. Doesn't take long to realize the tank will only get you 250 miles driving conservatively... and I would think it's safe to assume that in the first week of owning an S4, conservative driving is not in your vocabulary!

 

No, it definitely was not conservative.. and never will be haha. But actually, I was almost right at 250 miles on the tank before I filled it up. So at least now I know what my driving range is, too.. haha

 

Keep an eye on your oil levels, too, at least until you know how much you consume on average.