I had a quick question. This is kind of stumping me, so I wanted to see if anyone else has had this problem, and if the timing is being retarded, I need to know so that I can fix it.
Okay, when I run the Z at WOT, at about 5500 RPM I get what sounds like backfiring and the car feels like it is falling on its face. I had this once before and it went away, and now it's back. I get the car to about 185*, I run 91-93 octane, I have a ported MAF and a K&N filter. It feels to me like the PCM is pulling timing, but the "backfiring" has me really worried. I get absolutely NO pinging, but the backfire sounds like it is coming from the intake. The MAF is fine, and idle and the other fuctions of the car are fine, and no SES has come on, so I curious to know what this is and how to fix it. I have an LT4 KM on the way, but I don't want to mask the problem.
I know that you guys will be able to help, and I am looking forward to some advice!! Spring is here, and I can't be feathering the thing while running ricers!!!

 

ANYONE!! I am beginning to think that everyone would rather argue about brake rotors than to help a fellow gearhead out with a problem!

 

It's not that others would rather argue... it's just that these questions could lead in a dozen different directions and some of us can't get back to a thread every day.

Could very well be that you are having a fuel problem (actually could be a few things)... do you have a way to monitor fuel pressure? You could very well be leaning out in the upper revs. Do the basics first.... new fuel filter, fuel injector cleaner, etc.. Really need a way of seeing the fuel pressure at WOT runs though.

-Mindgame

 

You don't get backfiring from pcm timing retardation. You may have an opti or other igntion related problem.

 

PLEASE!! NOT THE OPTI-WORD!!!! I have replaced the fuel filter, I run a bottle of injector cleaner through about every 5,000 miles, and I use octane booster, because the best gas that we can get here is 91 octane.
Shoebox, I hope that it's not an ignition problem, if so, what could it be? I have replaced the plugs (wires on the way), and cleaned the MAF with electronic parts cleaner. I don't get any signs of ignition trouble at the lower RPMS, and at idle it is smoother than any other F-body I have driven. I don't have any scan tools (the wife put a block on all purchases), so that is why I'm trying to get some advice. One thing that did spring to mind though, was that I never had this problem until AFTER I ported the MAF. But, it was never as warm as it is now since we bought the car. I don't think that it's the MAF, because I have had no other driveablility issues other than this-unless this is what happens when you play with it.
If there are any suggestions that you can offer, let me know, jit would greatly help!!