I have a 1991 Z28 (L98). The car has new plugs, wires, cap, rotor, redone 24# SVO injectors. I am running a stock AUJP Bin w/ a 25.8 lbs/hr injector flow rate.

Anyway, the car ran fine a few weeks ago (minus some spark knock at WOT). BLMs registered right around 123-124. Went to start her up last week and it was running like crap at idle (seems like it is missing), and has no power whatsoever. Scanned it and the BLMs ranged from 122 to 144. I swapped a stock AUJP w/ stock flow rate and it ran at 108 BLMs, and pretty much ran the same. I just pulled the plug wires one by one and couldn't single out a missing cylinder.

I did run a bottle of water remover through the tank, since the symptoms are very similar to problems I've had before w/ bad gas.

Anyone have any ideas what could abruptly cause this problem? I've been told to pull the IAC and clean it (have to buy a socket to fit the sucker), but I wouldn't think this would happen overnight and cause problems at WOT as well.

Here is a link to a datamaster file w/ a recent trip (if anyone wants to look it over): http://sethirdgen.org/rumblin91/1215AUJP26pound.uni

 

Did you ask Bernard yet?

 

how does it run in open loop? ok? try disconnecting the O2 sensor and see what happens. sounds like an O2 taking a dump.

 

No, haven't asked Bernard personally. I had posted it on SE3GO, so either he overlooked it or didn't have anything to add. I may end up PMing him if I can get if figured out.

Mystikkal: It runs pretty poorly in open loop as well. I replaced the O2 sensor a couple of months ago.

I'm hoping the IAC cleaning will fix it, but I just have a hunch that that isn't the problem (or atleast the entire problem).

 

hmm. first off check for vacuum leaks. some vacuum leaks can be hard to find with the glorious TPI intake we have.

have you checked your Fuel Pressure yet?