Today I picked up my 01 A4 vert from a muffler shop with new OBX headers, X pipe without cats, and a used flomaster mufflers installed. It sounded incredible and first couple miles on my way home everything seemed fine.
Shortly after I started noticing that the car lost a LOT of power especially in lower rpms, The A4 became much less responsive,(a lot of lag) and sometimes the car would jerk forward without even me touching accelerator. The check engine light came on, first blinking and then stayed on. I did several 0-6- runs (on a closed road) and found that I lost almost 1 1/2 second. (it was 5 flat now it is 6.5) I plugged my diablo predator tuner and red the code, it showed the following code PO300 misfire!? I took the tune of and restored my backup tune and then the vert did not even have power to spin the wheels. It felt more like Honda civic acceleration. The milege went down big time as well!!!
I have a dual cone CAI, and a factory diablo tune in the car otherwise stock. The muffler guys called me earlier during installation and told me that the spark plugs and wires looked brittle and recommended getting new ones. I got only wires but decided to wait with plugs for a few weeks.
Tomorrow morning I am going back there with a lot of questions!!!
I spend 1500$ to gain HP, not to loose it!!! I need you guys opinions and advises as to what it is and what I should do
Thanks in advance for you help!!!
Victor

 

You mentioned X pipe without cats... don't you need cat "eliminators" to give the computer a signal from the cats? I paged thru Mid America real quick, and didn't see anything, but it seems to me that Jegs and some of the others sell them. May not be it, but you might check it out.

 

Any time you add headers you will need a re tune of the computer. Your a/f is affected among other things and your computer is freaking out. This is very common on these cars when you change out the exhaust and add headers.

 

I'm not sure if you can work out the tune on a Diablo. Most guys opt for a full scale dyno tune HP Tuners or EFI Live style.

 

Thanks for the response, I just tried driving around my subdivsion and discovered that the car stalls constantly, seems like it has gotten worse since my drive home from the shop. I was planning to go back to those guys and show them the car, but I am not sure that I can even make it to their place anymore.
I heard that headers make the a/f leaner, Is there any way to use the diablo predator to at least temporarily fix the problem (like changing a/f mixture to richer?) just so I can get to the shop

 

Did you run the codes in the DIC???

 

From what I have read about these type of mods,a full tune is needed.Good luck!

 

BY chance
what did you do with the o2 sensors? Move back to front and delete the rear? Put all 4 back in same place?

 

I did headers, exhaust and a CAI myself and my car ran fine without a tune. I would have them check to see if they put the O2 sensors that normally are back past the cats on the wrong sides when they reinstalled them. I 've heard this is a common mistake.

 

mine ran fine without a tune as well. Just wonderig if he accidently changed something.

my guess is the o2 sensors are wrong like you mentioned

 

check your spark plug wire to make sure none of them didn't get burnt.also check the connection from the wire to the plugs.sounds like the shop pulled an end off one of the wires when they were removing them.probably did a half-*** repair to the end and then recommened your getting new wires.
after i installed me lt's,i drove my car for 3 weeks before getting it tuned.never threw a code and always had more power than the stock exhaust did.

 

Make sure they reinstalled the Ground wire on the left side of the Block and double check the plug wires...

 

Your computer has to get use to the new parts now and will feel alittle sluggish for alittle bit. Drive the car around and have it re cal per say. Mine was like this as well but it will come around. A tune would be a plus! Jay

 

#1 Make sure the 02 sensors did not get crossed

#2 You probably have a cracked spark plug. Look closely at #6 and #7

#3 Bad plug wire

NOT IN THE TUNE


btw If you spent $1500 for OBX installed you got ripped. Sorry

 

O2 sensors could be reversed, if i recall the wires need to actually be crossed

 

My money is on the fact that the muffler shop crossed these wires. It's a common mistake.

While a full tune should be done, installing headers should not make the car run this poorly. When mine were installed, it was about 2 weeks before I had it tuned, and it ran fine.

Something is a miss mechanically!!! Good luck getting it straightened out.

 

First place I'd look would be wires and plugs!!

 

Because your shop JUST happen to mention them.

 

In my opinion a misfire is caused by 1 of the following. Plug, wire, coil or injector. Or on the outside chance of a valve train problem.

The cats may have clogged but highly unlikely.

They must have pulled the codes and found a P0302 if they told you it was cyl #2.

My bet is they cracked #2 spark plug. I don't think they needed to remove the coil packs to install the headers but I'm sure they removed the wires and plugs. This is where I would look first.

I would be concerned that they had to spend this much time on your car and they still don't have it fixed.

Just my 2 cents.

 

Good luck in finding your problem