Nor

Lately I have been having some problems. Under heavy acceleration I get some stuttering and exahust popping. In a heavy throttle run the first few gears seem to be fine. Boost is holding around 15 psi for a few seconds then the car studders and the exhaust pops as the boost tries to maintain 13-15psi. As my speeds/gear increase I have a problem. It seems like the car is trying to maintain proper boost levels but cant. I also get a popping sound coming from my exhaust. The car seems to hesitate/stutter during this time. Does this sound like a boost leak? To the best of my knowledge I don't have any vac. leaks but I know how that can quickly change. I recently replaced the plugs with NGK coppers and haven't noticed any unusual amounts of soot on my exhaust tips. Also, I replaced my ICM last year so I think thats fine.

Today I threw a CEL. The CEL doesnt stay consistant and I have only gotten it twice in the month that this has been happening. I hooked up the VAG and these were the results:

Chassis Type: 8D - Audi A4 B5
Scan: 01,02,03,08,15,17,25,35,45,55,56

Address 01 -------------------------------------------------------
Controller: 8D0 907 557 N
Component: 1.8l R4/5VT MOTR AT D03
Coding: 06251
Shop #: WSC 06325
4 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16688 - Shareware Version. To Decode all DTCs
P0304 - 35-10 - Please Register/Activate - Intermittent
16684 - Shareware Version. To Decode all DTCs
P0300 - 35-10 - Please Register/Activate - Intermittent
16688 - Shareware Version. To Decode all DTCs
P0304 - 35-10 - Please Register/Activate - Intermittent
Readiness: 0000 0000

I know its not the ICM because I replaced that last summer. To the best of my knowledge the coil packs are all original. From searching on AW, it seems that AEB motors have pretty solid coil packs, but based on these VAG results does it seem reasonable that I need a new coil pack?

Next off, if I need to purchase a new coil pack is the best method of installing just putting the new coil pack in, going for a drive to try and recreate the problem, and adjusting the location of the new coil pack based on if the problem reoccurs or not? If its not a coil pack could it be the maf?

Also here is a list of relevant mods that could be contributing factors to my problem:

1997 A4 1.8t auto
Neuspeed 1 bar chip
custom 2.5in exhaust
Labree downpipe
Labree HFC
Forge DV
newly installed KO3 w/ no shaft play
N75F
S4 motor mounts
fresh tranny mounts
APR snub mount
Samco hose from intercooler to throttle body
NGK copper plugs
less then a year old ICM

Thanks for the help.
Adam

briansailing

n75f could be problem or try moving around coil packs

Nor

Its just a revised version of the N75C thats put on newer 1.8t motors

shawfm

<ul><li><a href="http://www.bentleypublishers.com/tech/audi/audi.dtc.table.htm">Book Mark Me</a></li></ul>

ThirdEye

I have the same car with similar mods except I'm running a 97 K04 1Bar wheras you have a K03, however with my K03 I used to see 18-20psi wheras with my k04 I only see around 13-14psi.

Now two things that come to mind regarding boost leaks. I am running a different diverter valve than I was with the K03, as well as a fmic instead of the std smic. I'm sure the FMIC isn't leaking however I will try replacing the dv to see if it cures the problem.

The second thing regarding boost leaks is the L hose that runs into the PCV system. Now this has confused me because there is so little information on AW regarding our years. Appearantly the 97's didn't come with an L hose that connects into the intake manifold. However there was a recall that substituted something of the equivelant, however I have no way of knowing if it was indeed replaced. I checked all the hoses that run into the manifold and they all look to have no tears, however a simple boost leak test will not test anything besides for the intake system.

Now I noticed you also replaced the TB to intercooler hose, and I also had a tear in this hose, however after patching it, my boost stayed the same.

My next step is to try and whether upping the boost via a boost controller will keep the levels the same.

Nor

Wow that really is a nice resource. Thanks I sure did bookmark it.

Nor

Those should be fine. I run a forge dv with the second lightest spring. Perhaps I should try switching in the lightest spring or switch to my 710 dv.

ThirdEye

After doing some extensive research I have found that particularly with our years, the Turbo inlet tears where the DV goes into and it is easily missed.

Tomorow I am driving to PureMs and replacing the dv, turbo inlet, and throttle body hoses. Along with new vacuum lines. I will also attempt to relocate the diverter valve to the updated position on the turbo to intercooler pipe.

I will post my results so be sure to check back.

Nor

Sounds good. I'm interested to see your results