cocheese

Hey guys, here's the situation. I have a 94 a4 z and when i take off from a dead start, it pulls great through first gear and into second. In second when it gets to about 4000 rpm, it feels like it is suddenly loosing power, like it's stalling or surging. It does the same in third gear at 4000 under WOT. Also, i only get a SES light every so often, like when i'm cruising on the interstate at about 70 mph, and it only stays on for about 30 seconds to a minute. I put it on a diagnostic scanner and the guy told me that the right side O2 sensor was too lean. My mechanic told me he thought it might be the fuel pump so we replaced that. I don't think it's the filter, or the plug wires, cause they're both kinda new. I think the opti is original w/140,500 miles on it. Could it be that, or could it be a bad injector on the right side making it too lean? Any and all opinions are welcome! Thanks in advance guys!!

BlkScreaminMach

Its your opti, a burt wire, or a fuel pump.

If you got 140K on a possible original FP and opti, just replace them both, me and a close buddy went through that hassel of finding the problem.

First we did plugs and wires, and we fount 2 burnt wires, ok, well the symptoms didnt go away. Then we figure its the opti, so he does the opti, a new CSI elec wp, filters (all of them), and re asseble, SAME PROBLEM!!

Well stupid us we ddint check the fuel pressure from the rail. Turns out his car pump was out putting like 3 psi. Just enough to get it to idle.

CHECK your fuel pump! You should have between 41-45psi.

A faulty injector is not likely, but possible, but its a myth that it gets clogged, if this is happening at around 3K, its prob a opti issue, especially if the SES light comes on cus of emission reasons, maybe un burnt fuel, i.e. opti. or a burnt wire.

At worst go and get the car scanned.

IDOXLR8

You also may want to take a look at your igntion coil.

treyZ28

1 bad tank = !fuel filter

ill ride on the opti bandwagon today though