Engine cutting out/missing under load
The wife's '96 with less than 40k and the 4.6 has developed an issue.
First, the car has a few mods that were done when I got it. First, an open K&N cone on what appears to be a L-MAF, '98 Mustang plastic intake tube, underdrive pulleys, Dynomax cat-back exhaust and a chip. Unfortunately, I don't know who did the chip so this Spring Dennis will be getting an order for a new one.
Anyway, during the summer and fall I was getting a lot of detonation, even with mid- or high-octane fuel in 40 degree ambient air. It would ping at anything even close to or over 1/4 throttle in any gear. Suspecting the add-on chip and the programming, I made the wife was easy on it and new to downshift manually sometimes.
As it got down below freezing and the pinging became less of an issue, it started to act up during what I refer to as "tip-in." Take for instance, you leisurely get off a long off ramp, and when you get near the end of the ramp, and the tranny is still in OD with the converter locked, you ease back into the gas. Now, in this situation, the tranny really needs to downshift, but vehicle speed is fast enough and throttle demand is low enough that it doesnt do it. In this situation it would start "bucking" like a manual shift vehicle will do if you get into the pedal a little in too high of a gear. If you force a downshift, it stops it. It has quickly worsened and now I notice that under full throttle, I can feel it "missing" a bit, though it still pulls good. Otherwise, it runs and idles fine.
I started troubleshooting the pinging by cleaning the MAF and checking for pending codes, then left the battery disconnected (forgot about it and left it overnight, so it was long enough) to clear the computer. No dice.
Anyone have any ideas on what to start checking?
Last edited by Silkwood; 01-30-2004 at 06:56 PM.