agent64usa

Hi everyone, long time reader first time posting.

I have been struggling with my 95 A4 Z28 for almost a year now. It bogs down and sputters when at WOT and at high RPM. It's like it stops pulling at all even though I have the throttle wide open, if I maintain my foot on the throttle it sputters for a couple of seconds and then it recovers, or if I take my foot off of it for a second then it will be OK when I step on it again. It doesn't do it 100% of the time, more like 50% of the time. It also feels like it's down in power especially at higher RPM. I don't have any codes nor does the SES light come on. This is what I have done to try to get to the root of the problem:

1. Misting plug wires revealed arcing - changed wires and plugs
2. Changed fuel filter
3. Cleaned MAF w/ MAF cleaner
4. Tried to identify vacuum leak if any using break cleaner but didn't find any
5. Swapped out ignition coil and cable from coil to opti
6. Hooked up fuel pressure gage: 30psi at WOT, 40psi at priming

I did do some datalogging using scan9495 but not sure what to look for, I have attached the file hoping someone can help shed some light on this problem. Based on everything I have been reading over the past few months, I think it may come down to the opti, valve float, or fuel pump but still hoping it's something simpler.

Thanks in advance.

bufmatmuslepants

iTrader: (3)

Your low on fuel pressure, needs to be 42 all the time.

agent64usa

So you think weak/failing pump? According to previous owner, it's the stock setup.

cookseyb

Knock sensor pulling timing...

BALLSS

if your fuel pressure gauge is right "30 psi at wot"...is to low. The car would sputter and have no power as it is running WAY to lean

your fuel pump is tired and needs replacing