Sorry for the long read, just being descriptive.
Cliffs:
Low RPM misfires under increasing/high load
Comes and goes
No visible physical cause
Tried:
Swapping a spare TPS sensor: no change
Swapping injectors 4 and 6: no change
Swapping in a spare 3/6 ignition coil: no change
Tested for a vacuum leak: no change
Harsh language: no change
In-Depth:
So my 2000 GT is experiencing random misfires in the 1500-2200 RPM range when under high load. For instance, I'll be cruising in fourth gear and converter locked, doing 48 mph, and as I come to a slight hill, I tip into the throttle and it immediately begins to misfire, getting progressively worse, until I let off and tip in enough to downshift. It will misfire in this situation in second or third gear as well.
However, if I floor it at 35 mph, it'll grab first, pull with a stutter here and there, shift great, then pull through that gear with more hesitation as well. But if I'm on the highway doing 63 mph or ~2250 RPM it will only sometimes buck. It comes and goes without any notable pattern...
As this does not set a code unless I really abuse it, I'm thinking a component failure somewhere upstream of the plugs, as I've checked them all and they were immaculate. Once it finally threw a code and it gave me a cylinder 6 random misfire, but after inspecting the plug wire, plug, coil, and cps wiring, I could find nothing wrong. Start her up and voila, she's fine for a month and then it comes back...
Any ideas?
